:root {
    --primary: #0EA5E9;          /* sky-500 — đồng bộ sidebar */
    --primary-dark: #0284C7;     /* sky-600 */
    --primary-darker: #0369A1;   /* sky-700 */
    --primary-light: #F0F9FF;    /* sky-50 */
    --primary-soft: #E0F2FE;     /* sky-100 */
    --accent: #06B6D4;           /* cyan-500 */
    --accent-light: #CFFAFE;     /* cyan-100 */
    --accent-dark: #0E7490;      /* cyan-700 */
    --success: #22C55E;
    --success-mid: #BBF7D0;
    --success-light: #DCFCE7;
    --success-dark: #15803D;
    --gold: #F59E0B;
    --gold-light: #FEF3C7;
    --danger: #DC2626;
    --bg: #F8FAFC;               /* slate-50 */
    --bg-soft: #F1F5F9;          /* slate-100 */
    --bg-section: #E2E8F0;       /* slate-200 */
    --bg-card: #FFFFFF;
    --border: #E2E8F0;
    --border-soft: #F1F5F9;
    --text: #0F172A;             /* slate-900 */
    --text-soft: #475569;        /* slate-600 */
    --text-muted: #94A3B8;       /* slate-400 */
    --shadow-xs: 0 1px 2px rgba(15,23,42,0.04);
    --shadow-sm: 0 1px 3px rgba(15,23,42,0.06), 0 1px 2px rgba(15,23,42,0.04);
    --shadow: 0 4px 6px -1px rgba(15,23,42,0.08), 0 2px 4px -1px rgba(15,23,42,0.04);
    --shadow-lg: 0 20px 25px -5px rgba(15,23,42,0.12), 0 10px 10px -5px rgba(15,23,42,0.05);
    --shadow-glow: 0 8px 24px rgba(14,165,233,0.18);
    --shadow-pink: 0 8px 24px rgba(6,182,212,0.2);
  }

  * { margin: 0; padding: 0; box-sizing: border-box; }

  body {
    font-family: 'Be Vietnam Pro', system-ui, 'Segoe UI', sans-serif;
    background:
      radial-gradient(ellipse 1200px 600px at 0% 0%, rgba(0,120,174,0.05) 0%, transparent 50%),
      radial-gradient(ellipse 1000px 500px at 100% 100%, rgba(228,34,59,0.04) 0%, transparent 50%),
      var(--bg);
    background-attachment: fixed;
    color: var(--text);
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    font-size: 15px;
    line-height: 1.6;
    letter-spacing: normal;
  }

  h1, h2, h3, h4, h5 {
    font-family: 'Be Vietnam Pro', system-ui, 'Segoe UI', sans-serif;
    font-weight: 700;
    letter-spacing: normal;
    color: var(--text);
  }

  .view { display: none; }
  .view.active { display: block; }

  /* === LOGIN VIEW === */
  #login-view {
    display: none;
    min-height: 100vh;
    align-items: center;
    justify-content: center;
    padding: 24px;
    background:
      radial-gradient(ellipse 800px 600px at top right, var(--primary-soft) 0%, transparent 55%),
      radial-gradient(ellipse 600px 400px at bottom left, var(--accent-light) 0%, transparent 55%),
      var(--bg-soft);
  }
  #login-view.active { display: flex; }

  .login-card {
    background: var(--bg-card);
    border-radius: 24px;
    padding: 48px 48px 40px;
    width: 100%;
    max-width: 560px;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border);
    position: relative;
  }

  .login-logo {
    display: flex;
    justify-content: center;
    margin-bottom: 24px;
  }
  .login-logo img {
    width: 108px;
    height: 108px;
    object-fit: contain;
    filter: drop-shadow(0 12px 24px rgba(0,0,0,0.18));
    animation: logoFloat 3s ease-in-out infinite;
  }
  @keyframes logoFloat {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-6px); }
  }

  .login-title {
    font-size: 36px;
    text-align: center;
    margin-bottom: 8px;
    letter-spacing: -0.04em;
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
  }
  .login-subtitle-wrap {
    text-align: center;
    margin-bottom: 32px;
    min-height: 22px;
  }
  .login-subtitle {
    display: inline-block;
    font-size: 13.5px;
    color: var(--text-soft);
    font-weight: 500;
    white-space: nowrap;
    position: relative;
    letter-spacing: 0;
  }
  .login-subtitle::after {
    content: '|';
    color: var(--primary);
    margin-left: 2px;
    font-weight: 700;
    animation: blink 0.7s step-end infinite;
  }
  .login-subtitle.done::after { display: none; }
  @keyframes blink { 50% { opacity: 0; } }

  .form-group { margin-bottom: 18px; }
  .form-label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 8px;
    letter-spacing: 0;
  }
  .form-input {
    width: 100%;
    padding: 13px 16px;
    border: 1.5px solid var(--border);
    border-radius: 10px;
    font-family: inherit;
    font-size: 15px;
    font-weight: 500;
    background: var(--bg);
    transition: all 0.15s;
    color: var(--text);
  }
  .form-input::placeholder { color: var(--text-muted); font-weight: 400; }
  .form-input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(27,95,163,0.12);
  }

  .btn {
    border: 0;
    cursor: pointer;
    font-family: inherit;
    font-weight: 600;
    transition: all 0.15s;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    text-decoration: none;
    letter-spacing: -0.005em;
  }
  .btn-primary {
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    color: white;
    padding: 14px 24px;
    border-radius: 12px;
    font-size: 15px;
    font-weight: 700;
    letter-spacing: -0.005em;
    width: 100%;
    margin-top: 8px;
    border: 0;
    cursor: pointer;
    transition: all 0.25s;
    box-shadow: 0 4px 14px rgba(79,70,229,0.25), 0 2px 4px rgba(236,72,153,0.15);
    position: relative;
    overflow: hidden;
  }
  .btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(79,70,229,0.35), 0 4px 8px rgba(236,72,153,0.25);
  }
  .btn-primary:active {
    transform: translateY(0);
    box-shadow: 0 2px 8px rgba(79,70,229,0.25);
  }

  .login-footer {
    margin-top: 24px;
    text-align: center;
    font-size: 13px;
    color: var(--text-muted);
  }
  .login-footer b { color: var(--primary); font-weight: 600; }

  /* === DASHBOARD === */
  .topbar {
    background: rgba(250, 251, 255, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(99, 102, 241, 0.12);
    padding: 14px 32px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: sticky;
    top: 0;
    z-index: 50;
  }
  .topbar-brand { display: flex; align-items: center; gap: 14px; }
  .topbar-brand img {
    width: 44px;
    height: 44px;
    object-fit: contain;
    filter: drop-shadow(0 4px 8px rgba(99, 102, 241, 0.15));
  }
  .topbar-brand .brand-text {
    font-weight: 800;
    font-size: 17px;
    letter-spacing: -0.025em;
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
    line-height: 1.1;
  }
  .topbar-brand .brand-text small {
    display: block;
    font-size: 11px;
    color: var(--text-muted);
    font-weight: 500;
    margin-top: 2px;
    letter-spacing: 0.01em;
    -webkit-text-fill-color: var(--text-muted);
  }

  .topbar-actions { display: flex; align-items: center; gap: 12px; }

  .user-chip {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 5px 14px 5px 5px;
    background: var(--bg-soft);
    border-radius: 999px;
    border: 1px solid var(--border);
    cursor: pointer;
    transition: all 0.15s;
  }
  .user-chip:hover { background: var(--primary-light); border-color: var(--primary); }
  .avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 12px;
    letter-spacing: -0.02em;
  }
  .user-chip strong { font-size: 12.5px; font-weight: 700; white-space:nowrap; overflow:hidden; text-overflow:ellipsis; max-width:180px; display:block; }
  .user-chip small { display: block; font-size: 10.5px; color: var(--text-soft); font-weight: 500; }
  .avatar.avatar-sm { width:28px; height:28px; font-size:12px; }
  /* Hero stack (nút Hình ảnh học tập + avatar) */
  .hero-right-stack {
    position:absolute; top:18px; right:18px; z-index:2;
    display:flex; flex-direction:column; align-items:center; gap:14px;
  }
  .hero-right-stack .hero-photo-btn { position:static; margin:0; }
  .hero-right-stack .hero-avatar {
    width: 92px; height: 92px; border-radius: 50%;
    background: rgba(255,255,255,0.18);
    border: 3px solid rgba(255,255,255,0.5);
    box-shadow: 0 8px 22px rgba(0,0,0,0.18);
    overflow: hidden; color:#fff;
  }
  .hero-right-stack .hero-avatar img { width:100%; height:100%; object-fit:cover; border-radius:50%; }
  .hero-right-stack .hero-avatar-emoji { display:flex; align-items:center; justify-content:center; font-size:54px; }
  /* Mobile: gộp hàng ngang trên đầu hero, không đè progress bar */
  @media (max-width: 768px) {
    .hero-right-stack {
      position:static !important;
      flex-direction:row; justify-content:center;
      margin: 0 0 14px;
    }
    .hero-right-stack .hero-avatar { width:64px; height:64px; }
    .hero-right-stack .hero-avatar-emoji { font-size:36px; }
  }
  @media (max-width: 480px) {
    .hero-right-stack { gap:10px; }
    .hero-right-stack .hero-avatar { width:54px; height:54px; }
    .hero-right-stack .hero-avatar-emoji { font-size:30px; }
  }
  /* Tab buttons không xuống dòng */
  .tab-btn { white-space:nowrap; }
  /* Mobile: tab-nav full width, 3 nút chia đều, không tràn ngang */
  @media (max-width: 640px) {
    .tab-nav { width: 100% !important; box-sizing: border-box; }
    .tab-btn { flex: 1; padding: 8px 6px !important; font-size: 11.5px !important; min-width: 0; justify-content:center; }
    .tab-btn .badge { font-size: 9.5px !important; padding: 1px 5px !important; }
  }

  .btn-logout {
    border: 1px solid var(--border);
    background: white;
    color: var(--text-soft);
    cursor: pointer;
    font-family: inherit;
    font-size: 13px;
    font-weight: 500;
    padding: 8px 14px;
    border-radius: 8px;
    transition: all 0.15s;
  }
  .btn-logout:hover { background: var(--bg-soft); border-color: var(--text-muted); }

  /* Page hero */
  .page-container { max-width: 1200px; margin: 0 auto; padding: 28px 32px; }

  .hero-section {
    background:
      radial-gradient(ellipse 900px 500px at 100% 0%, rgba(236, 72, 153, 0.22) 0%, transparent 60%),
      radial-gradient(ellipse 700px 500px at 0% 100%, rgba(34, 211, 238, 0.14) 0%, transparent 60%),
      radial-gradient(ellipse 500px 400px at 80% 90%, rgba(168, 85, 247, 0.20) 0%, transparent 55%),
      linear-gradient(135deg, #4F46E5 0%, #6366F1 40%, #7C3AED 100%);
    border-radius: 24px;
    padding: 36px 40px;
    color: white;
    margin-bottom: 32px;
    position: relative;
    overflow: hidden;
    box-shadow: 0 20px 50px -12px rgba(79, 70, 229, 0.45), 0 8px 20px -6px rgba(124, 58, 237, 0.25);
  }
  .hero-section::before {
    content: '';
    position: absolute;
    top: -120px; right: -80px;
    width: 380px; height: 380px;
    background: radial-gradient(circle, rgba(236,72,153,0.15) 0%, rgba(236,72,153,0) 70%);
    border-radius: 50%;
    filter: blur(20px);
  }
  .hero-section::after {
    content: '';
    position: absolute;
    bottom: -100px; left: 30%;
    width: 280px; height: 280px;
    background: radial-gradient(circle, rgba(34,211,238,0.12) 0%, rgba(34,211,238,0) 70%);
    border-radius: 50%;
    filter: blur(25px);
  }
  .hero-content { position: relative; z-index: 1; }

  /* Nút "Hình ảnh học tập" ở góc phải hero */
  .hero-photo-btn {
    position: absolute;
    top: 24px;
    right: 24px;
    z-index: 3;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 16px;
    background: rgba(255,255,255,0.16);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255,255,255,0.28);
    border-radius: 12px;
    color: white;
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
    letter-spacing: -0.005em;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  }
  .hero-photo-btn:hover {
    background: rgba(255,255,255,0.26);
    border-color: rgba(255,255,255,0.45);
    transform: translateY(-2px);
    box-shadow: 0 6px 18px rgba(0,0,0,0.15);
  }
  .hero-photo-icon { font-size: 16px; }
  .hero-greeting { font-size: 14px; opacity: 0.88; margin-bottom: 4px; font-weight: 500; }
  .hero-name {
    font-size: 36px;
    margin-bottom: 6px;
    color: white;
    text-shadow: 0 2px 12px rgba(0,0,0,0.15);
  }
  .hero-tagline { font-size: 15px; opacity: 0.9; margin-bottom: 28px; font-weight: 400; }
  .hero-stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 14px;
    max-width: 780px;
  }

  .stat-bar {
    background: rgba(255,255,255,0.13);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    border: 1px solid rgba(255,255,255,0.22);
    padding: 12px 16px;
    border-radius: 14px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
  }

  .stat-bar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 8px;
    gap: 10px;
  }

  .stat-bar-title {
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    font-weight: 700;
    opacity: 0.88;
    white-space: nowrap;
  }

  .stat-bar-value, .stat-bar-tier {
    font-size: 13px;
    font-weight: 700;
    letter-spacing: -0.005em;
    display: inline-flex;
    align-items: center;
    gap: 5px;
    white-space: nowrap;
  }

  /* Tier dot - mini circle to indicate current tier color */
  .tier-dot {
    width: 11px;
    height: 11px;
    border-radius: 50%;
    flex-shrink: 0;
    background: #DCFCE7;
    border: 2px solid #4ADE80;
    transition: all 0.4s;
  }
  .tier-dot.tier-1 { background: #FEF9C3; border-color: #FDE047; }
  .tier-dot.tier-2 { background: #FCD34D; border-color: #D97706; }
  .tier-dot.tier-3 { background: #DCFCE7; border-color: #4ADE80; }
  .tier-dot.tier-4 { background: #86EFAC; border-color: #16A34A; }
  .tier-dot.tier-5 { background: #DDD6FE; border-color: #8B5CF6; }
  .tier-dot.empty { background: rgba(255,255,255,0.3); border-color: rgba(255,255,255,0.5); }

  /* Bar 1 - Tiến trình */
  .stat-bar-track {
    height: 10px;
    background: rgba(255,255,255,0.18);
    border-radius: 999px;
    overflow: hidden;
    position: relative;
  }
  .stat-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, #6366F1 0%, #EC4899 100%);
    border-radius: 999px;
    transition: width 0.7s cubic-bezier(0.34, 1.56, 0.64, 1);
    box-shadow: 0 0 10px rgba(99,102,241,0.45);
  }

  /* Thanh ĐÁNH GIÁ: gradient LIÊN TỤC chia 10 điểm, 4 màu nhóm */
  /* Mốc: 1-4 = Cần cố gắng (xanh viền trắng), 5-7 = Hoàn thành (xanh nhạt), 8-9 = Tốt (xanh đậm), 10 = Xuất sắc (tím) */
  .stat-bar-gradient {
    height: 14px;
    border-radius: 999px;
    position: relative;
    background: linear-gradient(90deg,
      #DCFCE7 0%,        /* 0 điểm — trắng xanh */
      #BBF7D0 40%,       /* 4 điểm — chuyển sang Hoàn thành */
      #86EFAC 50%,       /* 5 điểm — Hoàn thành */
      #4ADE80 70%,       /* 7 điểm — chuyển sang Tốt */
      #16A34A 80%,       /* 8 điểm — Tốt */
      #15803D 90%,       /* 9 điểm — chuyển sang Xuất sắc */
      #A78BFA 100%       /* 10 điểm — Xuất sắc */
    );
    border: 1.5px solid rgba(255,255,255,0.3);
    box-shadow: inset 0 1px 2px rgba(0,0,0,0.1);
  }
  /* Vạch chia 10 điểm (tick mark mờ trên thanh) */
  .stat-bar-gradient::before {
    content: '';
    position: absolute; inset: 0;
    background: repeating-linear-gradient(90deg,
      transparent 0, transparent calc(10% - 1px),
      rgba(255,255,255,.35) calc(10% - 1px), rgba(255,255,255,.35) 10%);
    border-radius: 999px;
    pointer-events: none;
  }

  .seg-marker {
    position: absolute;
    top: 50%;
    width: 20px;
    height: 20px;
    background: white;
    border: 3px solid #0ea5e9;
    border-radius: 50%;
    transform: translate(-50%, -50%);
    box-shadow: 0 3px 10px rgba(0,0,0,0.35), 0 0 0 2px rgba(255,255,255,0.5);
    z-index: 2;
    transition: left 0.7s cubic-bezier(0.34, 1.56, 0.64, 1), background 0.3s, border-color 0.3s;
  }
  .seg-marker.hidden { opacity: 0; transform: translate(-50%, -50%) scale(0.5); }

  /* Tabs */
  .tab-nav {
    display: flex;
    gap: 4px;
    background: white;
    padding: 5px;
    border-radius: 14px;
    border: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
    margin-bottom: 24px;
    width: fit-content;
  }
  .tab-btn {
    border: 0;
    background: transparent;
    padding: 10px 22px;
    border-radius: 10px;
    font-family: inherit;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-soft);
    cursor: pointer;
    transition: all 0.18s;
    display: flex;
    align-items: center;
    gap: 8px;
    letter-spacing: -0.005em;
  }
  .tab-btn:hover { color: var(--primary); background: var(--primary-light); }
  .tab-btn.active {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: white;
    box-shadow: 0 2px 8px rgba(79,70,229,0.25);
  }
  .tab-btn.active:hover { color: white; }
  .tab-btn.active .badge {
    background: rgba(255,255,255,0.25);
    color: white;
  }
  .tab-btn .badge {
    background: var(--bg-section);
    color: var(--text-soft);
    padding: 1px 8px;
    border-radius: 999px;
    font-size: 11px;
    font-weight: 700;
  }
  .tab-btn.active .badge {
    background: var(--primary-light);
    color: var(--primary);
  }

  .tab-pane { display: none; }
  .tab-pane.active { display: block; }

  /* === LESSON CARD (Code.org style) === */
  .lesson-card {
    background: white;
    border-radius: 16px;
    margin-bottom: 16px;
    display: grid;
    grid-template-columns: 1fr 220px;
    overflow: hidden;
    transition: all 0.25s;
    box-shadow: 0 1px 3px rgba(67,56,202,0.06), 0 4px 12px -2px rgba(67,56,202,0.05);
    border: 1px solid rgba(99,102,241,0.08);
  }
  .lesson-card:hover {
    box-shadow: 0 8px 24px -4px rgba(67,56,202,0.12), 0 4px 12px -2px rgba(67,56,202,0.08);
    transform: translateY(-1px);
  }
  .lesson-card.locked { opacity: 0.55; }
  .lesson-card.locked:hover { transform: none; box-shadow: 0 1px 3px rgba(67,56,202,0.06); }

  .lesson-main {
    padding: 24px 28px;
  }
  .lesson-header {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 10px;
  }
  .lesson-toggle {
    width: 22px; height: 22px;
    border: 0; background: transparent;
    cursor: pointer;
    display: flex; align-items: center; justify-content: center;
    color: var(--text);
    font-size: 11px;
  }
  /* CẤP 2: Bài học */
  .lesson-title {
    font-size: 14px;
    font-weight: 700;
    letter-spacing: -0.01em;
    color: #1e293b;                /* slate-800 */
  }
  .lesson-desc {
    font-size: 12.5px;
    color: var(--text-soft);
    line-height: 1.6;
    margin-bottom: 16px;
    margin-left: 30px;
    max-width: 760px;
  }
  .lesson-desc b { color: var(--text); font-weight: 600; }

  .task-row {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-left: 30px;
    margin-top: 12px;
  }
  /* CẤP 3: Nhiệm vụ (task-pill) — font 12px slate-600 */
  .task-pill {
    background: white;
    border: 1px solid var(--border);
    border-radius: 999px;
    padding: 5px 14px 5px 8px;
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 12px;
    font-weight: 500;
    color: #475569;                /* slate-600 */
    flex-shrink: 0;
  }
  .task-pill .ico { font-size: 14px; }
  .task-pill-label {
    font-size: 14px;
    font-weight: 600;
    color: var(--text);
    flex-shrink: 0;
  }

  .task-circles {
    display: flex;
    align-items: center;
    gap: 6px;
    flex-wrap: wrap;
    flex: 1;
  }
  .task-circles::before {
    content: '';
    width: 16px;
    height: 2px;
    background: var(--border);
    margin-right: 2px;
    flex-shrink: 0;
  }
  .task-circle {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: white;
    border: 1.5px solid #D1D5DB;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 13px;
    font-weight: 700;
    color: #9CA3AF;
    cursor: pointer;
    transition: all 0.18s;
    position: relative;
    flex-shrink: 0;
  }
  .task-circle:hover {
    transform: translateY(-3px);
    border-color: var(--primary);
    color: var(--primary);
    box-shadow: var(--shadow);
  }
  /* NV mô phỏng: hình thoi (xoay 45°) — chữ giữ thẳng */
  .task-circle.sim {
    width: 32px; height: 32px;
    border-radius: 5px;
    transform: rotate(45deg);
    font-size: 12px;
    margin: 6px 8px;   /* tách khoảng để diagonal không đè nhau */
  }
  .task-circle.sim > * { display:inline-block; transform: rotate(-45deg); }
  .task-circle.sim:hover { transform: rotate(45deg) translateY(-3px); }
  /* Nhóm 1 (điểm 1-4) — Cần cố gắng: viền xanh nền RỖNG */
  .task-circle.tier-g1 {
    background: white;
    border: 2.5px solid #22C55E;
    color: #16a34a;
  }
  .task-circle.tier-g1:hover { background: #F0FDF4; border-color: #16A34A; }
  /* Nhóm 2 (điểm 5-7) — Hoàn thành: Xanh nhạt */
  .task-circle.tier-g2 {
    background: #86EFAC;
    border: 2.5px solid #86EFAC;
    color: #14532D;
  }
  .task-circle.tier-g2:hover { background: #4ADE80; border-color: #4ADE80; }
  /* Nhóm 3 (điểm 8-9) — Tốt: Xanh đậm */
  .task-circle.tier-g3 {
    background: #16A34A;
    border: 2.5px solid #15803D;
    color: white;
  }
  .task-circle.tier-g3:hover { background: #15803D; border-color: #14532D; }
  /* Nhóm 4 (điểm 10) — Xuất sắc: Tím + glow + ⭐ */
  .task-circle.tier-g4 {
    background: #C4B5FD;
    border: 2.5px solid #7C3AED;
    color: #5B21B6;
    box-shadow: 0 4px 14px rgba(139,92,246,0.4), 0 0 0 4px rgba(139,92,246,0.15);
  }
  .task-circle.tier-g4:hover { background: #A78BFA; border-color: #7C3AED; transform: translateY(-3px) scale(1.05); }
  .task-circle.tier-g4::after {
    content: '⭐';
    position: absolute;
    top: -8px;
    right: -8px;
    font-size: 14px;
    filter: drop-shadow(0 1px 2px rgba(0,0,0,0.2));
  }
  /* HS đã tự đánh giá, đang chờ GV duyệt -> vàng nhạt */
  .task-circle.pending {
    background: #FEF3C7;
    color: #92400E;
    border-color: #FBBF24;
    box-shadow: 0 1px 4px rgba(251,191,36,.25);
  }
  .task-circle.pending:hover {
    background: #FDE68A;
    border-color: #F59E0B;
    color: #78350F;
  }
  /* Khóa */
  .task-circle.locked {
    background: var(--bg-section);
    color: var(--text-muted);
    border-color: var(--border-soft);
    cursor: not-allowed;
    opacity: 0.6;
  }
  .task-circle.locked:hover {
    transform: none;
    box-shadow: none;
    border-color: var(--border-soft);
    color: var(--text-muted);
    background: var(--bg-section);
  }

  /* Action sidebar on right of lesson card */
  .lesson-actions {
    background: var(--primary-light);
    border-left: 3px solid var(--primary);
    padding: 18px;
    display: flex;
    flex-direction: column;
    gap: 14px;
    justify-content: center;
  }

  /* Mini bars trong lesson sidebar */
  .lesson-mini-bar { width: 100%; }
  .lesson-mini-bar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 6px;
    gap: 8px;
  }
  .lesson-mini-bar-title {
    font-size: 10px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 700;
    color: var(--text-soft);
  }
  .lesson-mini-bar-value {
    font-size: 12px;
    font-weight: 700;
    color: var(--text);
    white-space: nowrap;
  }
  .lesson-progress-track {
    height: 8px;
    background: white;
    border: 1px solid var(--border);
    border-radius: 999px;
    overflow: hidden;
  }
  .lesson-progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary) 0%, var(--accent) 100%);
    border-radius: 999px;
    transition: width 0.6s ease;
  }
  /* Thanh Đánh giá per-lesson — đồng bộ thang 10 điểm với sidebar */
  .lesson-tier-gradient {
    height: 10px;
    border-radius: 999px;
    position: relative;
    background: linear-gradient(90deg,
      #DCFCE7 0%,
      #BBF7D0 40%,
      #86EFAC 50%,
      #4ADE80 70%,
      #16A34A 80%,
      #15803D 90%,
      #A78BFA 100%
    );
    border: 1px solid var(--border);
  }
  .lesson-tier-gradient::before {
    content: '';
    position: absolute; inset: 0;
    background: repeating-linear-gradient(90deg,
      transparent 0, transparent calc(10% - 1px),
      rgba(255,255,255,.4) calc(10% - 1px), rgba(255,255,255,.4) 10%);
    border-radius: 999px;
    pointer-events: none;
  }
  .lesson-tier-marker {
    position: absolute;
    top: 50%;
    width: 14px;
    height: 14px;
    background: white;
    border: 2.5px solid #22C55E;
    border-radius: 50%;
    transform: translate(-50%, -50%);
    box-shadow: 0 2px 6px rgba(0,0,0,0.2);
    z-index: 2;
    transition: left 0.6s cubic-bezier(0.34, 1.56, 0.64, 1), background 0.3s, border-color 0.3s;
  }
  .lesson-tier-marker.hidden { opacity: 0; transform: translate(-50%, -50%) scale(0); }

  /* Feedback pill button trong lesson sidebar */
  .feedback-pill {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    padding: 9px 11px;
    background: white;
    border: 1px solid var(--border);
    border-radius: 10px;
    cursor: pointer;
    font-family: inherit;
    font-size: 12px;
    font-weight: 600;
    transition: all 0.18s;
    margin-top: 4px;
    box-shadow: 0 1px 2px rgba(67,56,202,0.04);
  }
  .feedback-pill:hover:not(.empty) {
    border-color: var(--primary);
    background: var(--primary-light);
    transform: translateY(-1px);
    box-shadow: 0 4px 10px rgba(79,70,229,0.12);
  }
  .feedback-pill.empty {
    cursor: not-allowed;
    opacity: 0.55;
    background: transparent;
    border-style: dashed;
  }
  .feedback-pill-label {
    display: flex;
    align-items: center;
    gap: 6px;
    color: var(--text);
    flex: 1;
    text-align: left;
    min-width: 0;
  }
  .feedback-pill-icon { font-size: 14px; flex-shrink: 0; }
  .feedback-pill-text { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
  .feedback-pill-badge {
    font-size: 9px;
    padding: 3px 7px;
    border-radius: 999px;
    font-weight: 700;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    white-space: nowrap;
    flex-shrink: 0;
    margin-left: 6px;
  }
  .feedback-pill-badge.new {
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent-dark) 100%);
    color: white;
    box-shadow: 0 2px 6px rgba(236,72,153,0.35);
    animation: pulseBadge 2s ease-in-out infinite;
  }
  .feedback-pill-badge.read {
    background: var(--success-light);
    color: var(--success-dark);
  }
  @keyframes pulseBadge {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.07); }
  }

  /* Feedback Modal */
  .modal-feedback-card {
    max-width: 540px;
    width: 100%;
  }
  .modal-feedback-header {
    padding: 24px 28px 16px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 16px;
  }
  .modal-feedback-header h3 {
    font-size: 19px;
    margin-bottom: 4px;
    letter-spacing: -0.02em;
  }
  .modal-feedback-meta {
    font-size: 13px;
    color: var(--text-soft);
    margin: 0;
    font-weight: 500;
  }
  .modal-feedback-body {
    padding: 22px 28px;
  }
  .modal-feedback-content {
    font-size: 14.5px;
    line-height: 1.65;
    color: var(--text);
    background: var(--bg-soft);
    padding: 18px 20px;
    border-radius: 12px;
    border-left: 3px solid var(--primary);
  }
  .modal-feedback-content .fb-line {
    margin: 0 0 14px 0;
  }
  .modal-feedback-content .fb-line:last-child { margin-bottom: 0; }
  .modal-feedback-content .fb-line b { color: #0f172a; font-weight: 700; }
  .modal-feedback-actions {
    padding: 0 28px 24px;
    display: flex;
    justify-content: flex-end;
    gap: 12px;
  }
  .modal-feedback-actions .btn-primary {
    width: auto;
    margin: 0;
    padding: 10px 24px;
    font-size: 14px;
  }

  /* ===== MODAL TASK V2 ===== */
  /* ============ MODAL TASK V2 - COMPACT ============ */
  .modal-task-v2 {
    max-width: 680px;
    width: 100%;
    max-height: 92vh;
    display: flex;
    flex-direction: column;
    overflow: hidden;
  }

  .modal-task-header-v2 {
    padding: 14px 22px 10px;
    border-bottom: 1px solid var(--border);
  }
  .modal-task-header-row {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 12px;
    margin-bottom: 8px;
  }
  .modal-task-title-v2 {
    font-size: 18px;
    letter-spacing: -0.025em;
    line-height: 1.3;
    flex: 1;
    margin: 0;
  }
  .modal-task-meta-v2 {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
  }
  .task-code-v2 {
    font-size: 11.5px;
    font-weight: 600;
    color: var(--text-soft);
    background: var(--bg-section);
    padding: 3px 10px;
    border-radius: 7px;
    letter-spacing: 0;
  }
  .task-code-v2 span:first-child {
    color: var(--primary);
    font-weight: 700;
  }
  .task-status-badge {
    font-size: 10px;
    font-weight: 700;
    padding: 3px 10px;
    border-radius: 999px;
    text-transform: uppercase;
    letter-spacing: 0.04em;
  }
  .task-status-badge.done { background: var(--success-light); color: var(--success-dark); }
  .task-status-badge.todo { background: var(--bg-section); color: var(--text-muted); }

  .modal-task-tier-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 9px 22px;
    background: var(--bg-soft);
    border-bottom: 1px solid var(--border);
    gap: 12px;
  }
  .modal-task-tier-row.hidden { display: none; }
  .task-tier-display {
    display: flex;
    align-items: center;
    gap: 10px;
  }
  .task-tier-display .modal-tier-circle {
    width: 28px;
    height: 28px;
    flex-shrink: 0;
  }
  .task-tier-name {
    font-size: 13.5px;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 0;
  }
  .task-tier-display small {
    font-size: 9.5px;
    color: var(--text-soft);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    font-weight: 600;
  }
  .task-verify-note {
    display: flex;
    align-items: center;
    gap: 5px;
    font-size: 11.5px;
    font-weight: 600;
    padding: 4px 10px;
    border-radius: 999px;
    white-space: nowrap;
  }
  .task-verify-note.pending {
    background: #FEF3C7;
    color: #92400E;
  }
  .task-verify-note.verified {
    background: var(--success-light);
    color: var(--success-dark);
  }

  .modal-task-body-v2 {
    padding: 16px 22px;
    overflow-y: auto;
    overflow-x: hidden;
    flex: 1;
  }

  .task-section-v2 { margin-bottom: 14px; }
  .task-section-v2:last-child { margin-bottom: 0; }
  .task-section-title-v2 {
    font-size: 11.5px;
    font-weight: 700;
    margin: 0 0 8px;
    color: var(--text);
    text-transform: uppercase;
    letter-spacing: 0.05em;
  }
  .task-detail-text {
    font-size: 14.5px;
    line-height: 1.65;
    color: var(--text-soft);
    margin: 0;
  }

  /* === Task Resources Layout (1 nút lớn trái + 2 nút nhỏ stack phải) === */
  .task-resources-row {
    display: grid;
    grid-template-columns: 1.3fr 1fr;
    gap: 10px;
    margin-bottom: 14px;
  }
  .task-resources-stack {
    display: flex;
    flex-direction: column;
    gap: 8px;
  }
  .task-resource-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.2s;
    border-radius: 14px;
    font-family: inherit;
  }
  /* Nút lớn bên trái - "Nội dung nhiệm vụ" */
  .task-resource-main {
    flex-direction: column;
    gap: 10px;
    padding: 14px 12px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    color: white;
    border: 0;
    box-shadow: 0 4px 14px rgba(79,70,229,0.25);
    min-height: 116px;
  }
  .task-resource-main:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 22px rgba(79,70,229,0.38);
    background: linear-gradient(135deg, var(--primary-dark) 0%, var(--accent-dark) 100%);
  }
  .resource-icon-big {
    font-size: 32px;
    line-height: 1;
    filter: drop-shadow(0 2px 4px rgba(0,0,0,0.15));
  }
  .resource-label-big {
    font-size: 14px;
    font-weight: 700;
    line-height: 1.3;
    letter-spacing: -0.01em;
  }
  /* 2 nút nhỏ bên phải (stack dọc) */
  .task-resource-small {
    gap: 8px;
    padding: 10px 14px;
    background: white;
    border: 1.5px solid var(--border);
    color: var(--text);
    font-size: 13px;
    font-weight: 700;
    flex: 1;
    min-height: 54px;
  }
  .task-resource-small:hover {
    border-color: var(--primary);
    background: var(--primary-light);
    color: var(--primary);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(79,70,229,0.15);
  }
  .task-resource-small .resource-icon {
    font-size: 18px;
    flex-shrink: 0;
  }

  /* Required/Optional tags */
  .optional-tag, .required-tag {
    font-size: 9px;
    font-weight: 700;
    padding: 2px 7px;
    border-radius: 999px;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    margin-left: 6px;
    vertical-align: middle;
    display: inline-block;
  }
  .optional-tag {
    background: var(--bg-section);
    color: var(--text-muted);
  }
  .required-tag {
    background: rgba(236,72,153,0.12);
    color: var(--accent-dark);
  }

  /* Rate warning */
  .rate-warning {
    display: none;
    margin-top: 10px;
    padding: 9px 12px;
    background: linear-gradient(135deg, rgba(236,72,153,0.10) 0%, rgba(236,72,153,0.05) 100%);
    border: 1.5px solid var(--accent);
    border-radius: 10px;
    color: var(--accent-dark);
    font-size: 12.5px;
    font-weight: 600;
    align-items: center;
    gap: 7px;
  }
  .rate-warning.show {
    display: flex;
    animation: rateShake 0.45s ease;
  }
  .rate-warning-icon { font-size: 16px; flex-shrink: 0; }
  @keyframes rateShake {
    0%, 100% { transform: translateX(0); }
    15%, 45%, 75% { transform: translateX(-5px); }
    30%, 60%, 90% { transform: translateX(5px); }
  }

  /* Verified lock note */
  .verified-lock-note {
    display: none;
    margin-top: 10px;
    padding: 9px 12px;
    background: linear-gradient(135deg, rgba(34,197,94,0.08) 0%, rgba(34,197,94,0.04) 100%);
    border: 1.5px solid #6EE7B7;
    border-radius: 10px;
    color: var(--success-dark);
    font-size: 12.5px;
    font-weight: 600;
    align-items: center;
    gap: 7px;
  }
  .verified-lock-note.show { display: flex; }
  .verified-lock-icon { font-size: 16px; flex-shrink: 0; }

  /* Disabled states (khi GV đã xác nhận) */
  .selfrate-btn:disabled,
  .selfrate-btn.locked {
    cursor: not-allowed;
    opacity: 0.55;
  }
  .selfrate-btn:disabled:hover,
  .selfrate-btn.locked:hover {
    transform: none;
    box-shadow: none;
    border-color: var(--border);
    background: white;
  }
  .selfrate-btn.locked.active {
    opacity: 1;
    border-color: var(--success);
    background: var(--success-light);
    box-shadow: 0 4px 12px rgba(34,197,94,0.15);
  }
  .task-form-textarea:disabled {
    background: var(--bg-section);
    color: var(--text-soft);
    cursor: not-allowed;
    border-style: dashed;
  }
  .btn-task-submit:disabled,
  .btn-task-submit.locked {
    background: var(--bg-section) !important;
    color: var(--text-muted) !important;
    cursor: not-allowed;
    box-shadow: none !important;
    transform: none !important;
  }
  .btn-task-submit:disabled:hover,
  .btn-task-submit.locked:hover {
    transform: none !important;
    box-shadow: none !important;
  }

  /* Form fields */
  .task-form-field { margin-bottom: 12px; }
  .task-form-field:last-child { margin-bottom: 0; }
  .task-form-label {
    display: block;
    font-size: 12px;
    font-weight: 600;
    margin-bottom: 6px;
    color: var(--text);
  }
  .task-form-textarea {
    width: 100%;
    padding: 9px 12px;
    border: 1px solid var(--border);
    border-radius: 10px;
    font-family: inherit;
    font-size: 13.5px;
    resize: vertical;
    background: var(--bg-soft);
    transition: all 0.18s;
    color: var(--text);
    min-height: 56px;
  }
  .task-form-textarea::placeholder {
    font-size: 11.5px;
    font-style: italic;
    color: #94a3b8;
    opacity: 1;
  }
  .task-form-textarea:focus {
    outline: none;
    border-color: var(--primary);
    background: white;
    box-shadow: 0 0 0 3px rgba(79,70,229,0.15);
  }

  /* Self-rate selector */
  .task-selfrate {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
  }
  .selfrate-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    padding: 9px 6px;
    background: white;
    border: 2px solid var(--border);
    border-radius: 12px;
    cursor: pointer;
    font-family: inherit;
    text-align: center;
    transition: all 0.18s;
  }
  .selfrate-btn:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
    box-shadow: 0 4px 10px rgba(79,70,229,0.15);
  }
  .selfrate-btn.active {
    border-color: var(--primary);
    background: var(--primary-light);
    box-shadow: 0 4px 10px rgba(79,70,229,0.2);
  }
  .selfrate-btn .modal-tier-circle {
    width: 26px;
    height: 26px;
  }
  .selfrate-btn .selfrate-label {
    font-size: 10.5px;
    font-weight: 700;
    line-height: 1.2;
    color: var(--text);
  }
  .selfrate-btn .selfrate-label small {
    font-weight: 500;
    color: var(--text-soft);
    font-size: 9.5px;
    display: block;
    margin-top: 1px;
  }
  .selfrate-btn .selfrate-emoji { font-size: 16px; line-height: 1; }

  /* Footer */
  .modal-task-footer-v2 {
    padding: 11px 22px;
    border-top: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    gap: 10px;
    background: var(--bg-soft);
  }
  .btn-task-cancel {
    padding: 9px 22px;
    background: white;
    border: 1px solid var(--border);
    border-radius: 10px;
    cursor: pointer;
    font-family: inherit;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-soft);
    transition: all 0.18s;
  }
  .btn-task-cancel:hover {
    background: var(--bg-section);
    color: var(--text);
  }
  .btn-task-submit {
    flex: 1;
    padding: 10px 22px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    color: white;
    border: 0;
    border-radius: 10px;
    cursor: pointer;
    font-family: inherit;
    font-size: 13.5px;
    font-weight: 700;
    letter-spacing: -0.005em;
    transition: all 0.25s;
    box-shadow: 0 4px 12px rgba(79,70,229,0.3);
  }
  .btn-task-submit:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 18px rgba(79,70,229,0.4);
  }

  /* ============ RESPONSIVE - TABLET ============ */
  @media (max-width: 768px) {
    .modal-overlay { padding: 8px; }
    .modal-task-v2 { max-height: 96vh; border-radius: 14px; }
    .modal-task-header-v2 { padding: 12px 16px 8px; }
    .modal-task-title-v2 { font-size: 16px; }
    .modal-task-tier-row { padding: 8px 16px; }
    .modal-task-body-v2 { padding: 12px 16px; }
    .modal-task-footer-v2 { padding: 10px 16px; }
    .task-section-v2 { margin-bottom: 12px; }
  }

  /* ============ RESPONSIVE - MOBILE ============ */
  @media (max-width: 540px) {
    .task-resources-row {
      grid-template-columns: 1fr;
      gap: 8px;
    }
    .task-resource-main {
      flex-direction: row;
      gap: 12px;
      min-height: 64px;
      padding: 12px 14px;
      justify-content: flex-start;
      text-align: left;
    }
    .resource-icon-big { font-size: 26px; }
    .resource-label-big { font-size: 14px; }
    .task-resources-stack {
      flex-direction: row;
      gap: 8px;
    }
    .task-resource-small {
      min-height: 50px;
      padding: 8px 10px;
      font-size: 12.5px;
      flex-direction: row;
    }
    .task-resource-small .resource-icon { font-size: 16px; }
    /* Self-rate vẫn 4 cột nhưng nhỏ hơn */
    .task-selfrate { gap: 6px; }
    .selfrate-btn { padding: 7px 4px; gap: 3px; }
    .selfrate-btn .modal-tier-circle { width: 22px; height: 22px; }
    .selfrate-btn .selfrate-label { font-size: 9.5px; }
    .selfrate-btn .selfrate-label small { font-size: 9px; }
    .selfrate-btn .selfrate-emoji { font-size: 14px; }
    .btn-task-cancel { padding: 9px 14px; font-size: 12.5px; }
    .btn-task-submit { padding: 10px 16px; font-size: 13px; }
    .modal-task-tier-row {
      flex-wrap: wrap;
      gap: 8px;
    }
    .task-verify-note { font-size: 11px; padding: 3px 9px; }
  }

  /* Legacy lesson-progress-mini - giữ lại CSS để không break nếu còn dùng đâu đó */
  .lesson-progress-mini {
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: 12px;
    color: var(--text-soft);
    font-weight: 600;
    margin-bottom: 4px;
  }

  /* Section header */
  .section-header {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    margin-bottom: 16px;
    padding-bottom: 4px;
  }
  .section-header h2 {
    font-size: 22px;
    letter-spacing: -0.03em;
    color: var(--text);
    display: flex;
    align-items: center;
    gap: 10px;
  }
  .section-header h2::before {
    content: '';
    display: inline-block;
    width: 4px;
    height: 22px;
    background: linear-gradient(180deg, var(--primary) 0%, var(--accent) 100%);
    border-radius: 4px;
  }
  .section-header p {
    font-size: 14px;
    color: var(--text-soft);
    margin-top: 4px;
    font-weight: 400;
  }

  /* === MODAL === */
  .modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(15,23,42,0.6);
    backdrop-filter: blur(4px);
    z-index: 200;
    display: none;
    align-items: center;
    justify-content: center;
    padding: 20px;
    animation: fadeIn 0.15s;
  }
  @keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
  .modal-overlay.active { display: flex; }

  .modal {
    background: var(--bg-card);
    border-radius: 16px;
    width: 100%;
    max-width: 680px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
    animation: slideUp 0.2s;
  }
  @keyframes slideUp { from { transform: translateY(20px); opacity: 0; } to { transform: translateY(0); opacity: 1; } }

  .modal-header {
    padding: 24px 28px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 16px;
    position: sticky;
    top: 0;
    background: white;
    z-index: 10;
  }
  .modal-title-block { flex: 1; }
  .modal-title { font-size: 22px; margin-bottom: 6px; letter-spacing: -0.03em; }
  .modal-subtitle { font-size: 13px; color: var(--text-soft); font-weight: 500; display: flex; align-items: center; gap: 8px; }
  .modal-subtitle .code {
    background: var(--primary-light); color: var(--primary);
    padding: 2px 8px; border-radius: 5px; font-size: 11px;
    font-weight: 700; letter-spacing: 0.02em;
  }
  .modal-status-badge {
    background: var(--success-light); color: var(--success);
    padding: 4px 10px; border-radius: 999px; font-size: 11px;
    font-weight: 700; letter-spacing: 0.02em; text-transform: uppercase;
  }
  .modal-status-badge.todo { background: var(--gold-light); color: #92400E; }
  .modal-close {
    border: 0;
    background: var(--bg-soft);
    width: 32px; height: 32px;
    border-radius: 8px;
    cursor: pointer;
    color: var(--text-soft);
    font-size: 16px;
    font-weight: 600;
    flex-shrink: 0;
  }
  .modal-close:hover { background: var(--border); }
  .modal-fs-btn { margin-left: 0; margin-right: 6px; }
  .modal-fs-btn:hover { background: #dbeafe; color: #2563eb; }
  .modal.expanded,
  .modal.modal-task-v2.expanded { max-width: 96vw !important; width: 96vw !important; max-height: 94vh !important; }
  .modal.expanded .modal-body,
  .modal.expanded .modal-task-body-v2 { max-height: calc(94vh - 130px) !important; }
  .modal-body { padding: 24px 28px; }

  .info-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 10px; margin-bottom: 20px; }
  .info-pill {
    background: var(--bg-soft);
    padding: 12px 14px;
    border-radius: 10px;
    border: 1px solid var(--border-soft);
  }
  .info-pill .label { font-size: 10px; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.06em; font-weight: 700; }
  .info-pill .value { font-size: 14px; font-weight: 700; margin-top: 2px; color: var(--text); }

  .section-title-modal {
    font-size: 12px;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 10px;
    margin-top: 22px;
    text-transform: uppercase;
    letter-spacing: 0.06em;
  }
  .modal-text { font-size: 14px; line-height: 1.7; color: var(--text-soft); }

  .material-list { display: flex; flex-wrap: wrap; gap: 6px; }
  .material-tag {
    background: var(--primary-light);
    color: var(--primary-dark);
    padding: 4px 10px;
    border-radius: 6px;
    font-size: 12px;
    font-weight: 600;
  }

  /* Existing rating display (for done tasks) */
  .rating-display {
    background: var(--success-light);
    border: 1px solid #6EE7B7;
    border-radius: 12px;
    padding: 16px 20px;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
  }
  .rating-display .left { display: flex; align-items: center; gap: 14px; }
  .rating-score {
    background: white;
    border-radius: 10px;
    padding: 6px 14px;
    font-size: 20px;
    font-weight: 800;
    color: var(--success);
    letter-spacing: -0.02em;
  }
  .modal-tier-circle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 38px;
    height: 38px;
    border-radius: 50%;
    font-weight: 800;
    font-size: 16px;
    line-height: 1;
    position: relative;
    box-sizing: border-box;
  }
  .modal-tier-circle.tier-1 { background: #fff;    border: 2.5px solid #86EFAC; color: #166534; }
  .modal-tier-circle.tier-2 { background: #BBF7D0; border: 2.5px solid #86EFAC; color: #14532D; }
  .modal-tier-circle.tier-3 { background: #16A34A; border: 2.5px solid #15803D; color: #fff; }
  .modal-tier-circle.tier-4 { background: #A78BFA; border: 2.5px solid #7C3AED; color: #fff; box-shadow: 0 4px 12px rgba(139,92,246,0.35); }
  .modal-tier-circle.tier-4::after {
    content: '⭐';
    position: absolute;
    top: -10px;
    right: -10px;
    font-size: 14px;
    filter: drop-shadow(0 1px 2px rgba(0,0,0,0.2));
  }
  .rating-display .grade {
    font-size: 14px;
    font-weight: 600;
    color: var(--success);
  }
  .rating-display .grade small { display: block; font-size: 11px; color: var(--text-soft); font-weight: 500; }

  .modal-footer {
    padding: 18px 28px;
    border-top: 1px solid var(--border);
    display: flex;
    gap: 10px;
    justify-content: flex-end;
    position: sticky;
    bottom: 0;
    background: white;
  }
  .btn-secondary {
    padding: 11px 20px;
    background: white;
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: 9px;
    font-family: inherit;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
  }
  .btn-secondary:hover { background: var(--bg-soft); }
  .btn-primary-sm {
    padding: 11px 22px;
    background: var(--primary);
    color: white;
    border: 0;
    border-radius: 9px;
    font-family: inherit;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
  }
  .btn-primary-sm:hover { background: var(--primary-dark); }

  /* === RUBRIC FORM === */
  .rubric-criterion {
    background: var(--bg-soft);
    padding: 16px;
    border-radius: 10px;
    border: 1px solid var(--border-soft);
    margin-bottom: 10px;
  }
  .rubric-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 10px; }
  .rubric-name { font-weight: 600; font-size: 14px; }
  .rubric-name span {
    background: var(--primary);
    color: white;
    width: 22px; height: 22px;
    border-radius: 6px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    margin-right: 8px;
    font-size: 12px;
  }
  .rubric-score { font-size: 20px; font-weight: 800; color: var(--primary); letter-spacing: -0.02em; }
  .rubric-options { display: grid; grid-template-columns: repeat(4, 1fr); gap: 6px; }
  .rubric-opt {
    background: white;
    border: 1.5px solid var(--border);
    border-radius: 8px;
    padding: 10px 6px;
    cursor: pointer;
    text-align: center;
    transition: all 0.15s;
  }
  .rubric-opt:hover { border-color: var(--primary); background: var(--primary-light); }
  .rubric-opt.selected {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
  }
  .rubric-opt .num { font-size: 18px; font-weight: 800; letter-spacing: -0.02em; }
  .rubric-opt .desc { font-size: 10px; color: var(--text-soft); line-height: 1.3; margin-top: 2px; }
  .rubric-opt.selected .desc { color: rgba(255,255,255,0.85); }

  .rubric-total {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    padding: 18px 22px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: 14px;
  }
  .rubric-total-label { font-size: 13px; opacity: 0.85; font-weight: 500; }
  .rubric-total-value { font-size: 30px; font-weight: 800; letter-spacing: -0.03em; }
  .rubric-total-grade {
    background: var(--success); color: white;
    padding: 6px 14px; border-radius: 999px; font-size: 13px; font-weight: 700;
  }

  .upload-zone {
    border: 2px dashed var(--border);
    border-radius: 10px;
    padding: 22px;
    text-align: center;
    color: var(--text-soft);
    cursor: pointer;
    transition: all 0.15s;
    background: var(--bg-soft);
  }
  .upload-zone:hover { border-color: var(--primary); background: var(--primary-light); }
  .upload-icon { font-size: 26px; margin-bottom: 8px; }
  .upload-zone .main-text { font-weight: 600; font-size: 14px; color: var(--text); }
  .upload-zone small { font-size: 12px; margin-top: 4px; display: block; }

  textarea.form-input { font-family: inherit; resize: vertical; min-height: 80px; }

  /* Toast */
  .toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--text);
    color: white;
    padding: 12px 24px;
    border-radius: 999px;
    font-size: 14px;
    font-weight: 500;
    z-index: 300;
    opacity: 0;
    transition: all 0.3s;
    box-shadow: var(--shadow-lg);
  }
  .toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

  /* Demo banner */
  .demo-banner {
    background: var(--text);
    color: white;
    padding: 8px 16px;
    text-align: center;
    font-size: 12px;
    font-weight: 500;
    letter-spacing: 0.01em;
  }
  .demo-banner b { font-weight: 700; color: var(--gold); }

  @media (max-width: 820px) {
    .hero-stats { grid-template-columns: 1fr; }
  }

  @media (max-width: 768px) {
    .topbar { padding: 10px 14px; gap: 8px; }
    .topbar-brand img { width: 36px; height: 36px; }
    .topbar-brand .brand-text { font-size: 15px; }
    .topbar-brand .brand-text small { display: none; }
    .user-chip { padding: 4px 10px 4px 4px; }
    .user-chip .avatar { width: 28px; height: 28px; font-size: 11px; }
    .user-chip strong { font-size: 12px; }
    .user-chip small { font-size: 10px; }
    .btn-logout { padding: 6px 10px; font-size: 12px; }

    .page-container { padding: 14px 12px 40px; }
    .hero-section { padding: 20px 18px 22px; border-radius: 18px; }
    .hero-greeting { font-size: 12px; }
    .hero-name { font-size: 24px; }
    .hero-tagline { font-size: 13px; margin-bottom: 16px; }

    .hero-photo-btn {
      position: static;
      display: inline-flex;
      margin-bottom: 14px;
      padding: 8px 12px;
      font-size: 12px;
    }
    .hero-photo-icon { font-size: 14px; }

    .stat-bar { padding: 10px 14px; }
    .stat-bar-header { gap: 8px; }
    .stat-bar-title { font-size: 12px; }
    .stat-bar-value { font-size: 12px; }

    .tab-nav { gap: 2px; padding: 4px; }
    .tab-btn { padding: 8px 12px; font-size: 13px; }
    .tab-btn .badge { font-size: 10px; padding: 1px 6px; }

    .lesson-card { grid-template-columns: 1fr; }
    .lesson-actions {
      border-left: 0;
      border-top: 3px solid var(--primary);
      flex-direction: row;
      gap: 14px;
      padding: 14px;
      flex-wrap: wrap;
    }
    .lesson-mini-bar { flex: 1; min-width: 140px; }
    .lesson-desc, .task-row { margin-left: 0; }
    .rubric-options { grid-template-columns: 1fr 1fr; }

    /* Login on mobile */
    .login-card { padding: 32px 24px 28px; }
    .login-logo img { width: 84px; height: 84px; }
    .login-title { font-size: 26px; }
    .login-subtitle, .login-subtitle-wrap { font-size: 13px; }
  }

  @media (max-width: 480px) {
    .topbar-brand .brand-text { font-size: 14px; }
    .user-chip > div { display: none; }
    .user-chip { padding: 4px; }
    .lesson-card .card-header { padding: 14px 16px; }
    .lesson-title { font-size: 13.5px; }
    .task-circles { gap: 4px; }
    .hero-name { font-size: 22px; }
  }

  /* ============ MOBILE PASS — toàn cục ============ */
  @media (max-width: 640px) {
    .hero-stats { grid-template-columns: 1fr; gap: 10px; }
    .modal-task-v2 { max-width: 96vw !important; max-height: 92vh; }
    .modal-task-header-v2 { padding: 14px 16px 10px; }
    .modal-task-body-v2 { padding: 14px 16px; max-height: 60vh; }
    .modal-task-footer-v2 { padding: 12px 16px; gap: 8px; flex-wrap: wrap; }
    .modal-task-footer-v2 .btn-secondary,
    .modal-task-footer-v2 .btn-task-submit { flex: 1; min-width: 130px; padding: 12px; font-size: 14px; }
    .task-resources-row { flex-direction: column; gap: 10px; }
    .task-resources-stack { flex-direction: row !important; }
    .task-resource-btn { flex: 1; }
    .task-resource-main { min-height: 90px !important; }
    .task-selfrate { grid-template-columns: 1fr 1fr; gap: 8px; }
    .selfrate-btn { padding: 10px 6px !important; }
    .modal-task-tier-row { flex-direction: column; align-items: flex-start !important; gap: 8px; }
    .modal-feedback-card { max-width: 96vw !important; }
  }
  @media (max-width: 380px) {
    .topbar { padding: 6px 10px; gap: 6px; }
    .topbar-brand { gap: 6px; }
    .topbar-brand img, .topbar-brand svg { width: 32px; height: 32px; }
    .topbar-brand .brand-text { font-size: 13px; }
    .topbar-brand small { display: none; }
    .hero-name { font-size: 20px; }
    .lesson-title { font-size: 13px; }
  }

/* CẤP 1: HS Topic (Chủ đề) — sky/slate */
.hs-topic-card {
  background: #fff;
  border: 1.5px solid #bae6fd;       /* sky-200 */
  border-radius: 14px;
  margin-bottom: 14px;
  overflow: hidden;
  box-shadow: 0 1px 3px rgba(15,23,42,.04);
}
.hs-topic-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 12px 16px;
  background: linear-gradient(135deg, #f0f9ff 0%, #e0f2fe 100%);
  border-bottom: 1.5px solid #bae6fd;
  cursor: pointer;
  user-select: none;
}
.hs-topic-title {
  font-weight: 700;
  font-size: 15.5px;
  color: #0f172a;                    /* slate-900 */
  letter-spacing: -.005em;
  display: flex;
  align-items: center;
  gap: 8px;
  flex: 1;
  min-width: 0;
}
.hs-topic-chevron {
  color: #0ea5e9;
  font-size: 11px;
  transition: transform .2s;
  display: inline-block;
}
.hs-topic-card.collapsed .hs-topic-chevron { transform: rotate(-90deg); }
.hs-topic-card.collapsed .hs-topic-body { display: none; }
.hs-topic-meta { display: flex; align-items: center; gap: 8px; }
.hs-topic-info {
  font-size: 11.5px;
  color: #0284c7;
  font-weight: 700;
  background: #e0f2fe;
  padding: 4px 10px;
  border-radius: 999px;
  white-space: nowrap;
}
.hs-topic-body { padding: 14px 16px; }
.hs-topic-body .lesson-card { margin-bottom: 10px; }
.hs-topic-body .lesson-card:last-child { margin-bottom: 0; }

/* Thanh chọn Chương trình (HS) — nằm trên thanh tab Khóa học */
.program-tab-nav {
  display: flex;
  gap: 10px;
  margin: 14px 0 6px;
  flex-wrap: wrap;
}
.program-tab-nav:empty { display: none; }
.program-tab-btn {
  padding: 10px 20px;
  border-radius: 999px;
  border: 1px solid var(--border, #e5e7eb);
  background: #fff;
  cursor: pointer;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-soft, #4b5563);
  transition: all .18s;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.program-tab-btn:hover {
  border-color: #6366f1;
  color: #4338ca;
  background: #eef2ff;
}
.program-tab-btn.active {
  background: linear-gradient(135deg, #4f46e5 0%, #ec4899 100%);
  color: #fff;
  border-color: transparent;
  box-shadow: 0 4px 12px rgba(79,70,229,.25);
}
.program-tab-name { letter-spacing: -.01em; }

/* Thu gọn bài học (HS) — bấm vào header bài để đóng/mở nội dung */
.lesson-header { cursor: pointer; user-select: none; }
.lesson-toggle { transition: transform .2s ease; }
.lesson-card.collapsed .lesson-toggle { transform: rotate(-90deg); }
.lesson-card.collapsed .lesson-desc,
.lesson-card.collapsed .task-row,
.lesson-card.collapsed .lesson-actions { display: none !important; }
.lesson-card.collapsed .lesson-main { padding-bottom: 16px; }
.lesson-card.collapsed .lesson-header { margin-bottom: 0; }
@media (max-width: 480px) {
  .hs-topic-header { padding: 10px 12px; }
  .hs-topic-title { font-size: 14px; }
  .hs-topic-body { padding: 10px; }
}


/* Reopen banner + history */
.task-reopen-banner{background:#fff7ed;border-left:4px solid #fb923c;color:#9a3412;padding:12px 14px;border-radius:8px;margin:0 0 14px;font-size:14px;line-height:1.45}
.task-history-details{background:#f8fafc;border-left:3px solid #fb923c;border-radius:6px;padding:8px 12px;font-size:13px}
.task-history-details summary{cursor:pointer;font-weight:600;color:#92400e;padding:4px 0}
.task-history-details ul{margin:6px 0 4px 18px;padding:0;color:#475569}
.task-history-details li{margin:4px 0;line-height:1.5}

/* ── Notifications (bell + dropdown panel) ───────────────────────────── */
.notif-wrap{position:relative;display:inline-block;margin-right:8px}
.notif-bell{background:transparent;border:none;cursor:pointer;font-size:22px;line-height:1;padding:6px 8px;border-radius:8px;position:relative;color:inherit;transition:background .15s}
.notif-bell:hover{background:rgba(255,255,255,.18)}
.notif-count{position:absolute;top:-2px;right:-2px;background:#ef4444;color:#fff;font-size:11px;font-weight:700;min-width:18px;height:18px;padding:0 5px;border-radius:9px;display:inline-flex;align-items:center;justify-content:center;line-height:1;border:2px solid #fff;box-sizing:border-box}
.notif-panel{position:absolute;top:calc(100% + 8px);right:0;width:360px;max-height:480px;background:#fff;border-radius:12px;box-shadow:0 10px 32px rgba(15,23,42,.18),0 2px 6px rgba(15,23,42,.08);z-index:2000;display:flex;flex-direction:column;overflow:hidden;border:1px solid #e5e7eb}
.notif-panel[hidden]{display:none !important}
.notif-header{display:flex;align-items:center;justify-content:space-between;padding:12px 14px;border-bottom:1px solid #f1f5f9;background:#fafbfc;flex-shrink:0}
.notif-header h4{margin:0;font-size:15px;color:#1f2937;font-weight:700}
.notif-mark-all{background:transparent;border:none;color:#4f46e5;font-size:12px;cursor:pointer;padding:4px 8px;border-radius:6px;font-weight:600}
.notif-mark-all:hover{background:#eef2ff}
.notif-list{overflow-y:auto;flex:1;min-height:80px}
.notif-empty{padding:32px 16px;text-align:center;color:#94a3b8;font-size:13px}
.notif-item{display:flex;align-items:flex-start;gap:10px;padding:10px 14px;border-bottom:1px solid #f1f5f9;cursor:pointer;position:relative;transition:background .12s}
.notif-item:hover{background:#f8fafc}
.notif-item.unread{background:#eff6ff}
.notif-item.unread:hover{background:#dbeafe}
.notif-icon{font-size:18px;line-height:1.2;flex-shrink:0;width:26px;text-align:center}
.notif-main{flex:1;min-width:0}
.notif-title{font-size:13px;color:#1f2937;line-height:1.4;word-break:break-word}
.notif-item.unread .notif-title{font-weight:600}
.notif-item:not(.unread) .notif-title{color:#64748b}
.notif-body{font-size:12px;color:#64748b;margin-top:3px;line-height:1.4;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.notif-time{font-size:11px;color:#94a3b8;margin-top:4px}
.notif-dot{width:8px;height:8px;background:#3b82f6;border-radius:50%;flex-shrink:0;margin-top:6px}
@media (max-width:480px){
  .notif-panel{width:calc(100vw - 24px);right:-8px;max-width:360px}
}

/* ── Cascading notification badges (program/course/topic/lesson/task) ── */
.hs-notif-dot{
  display:inline-flex;align-items:center;justify-content:center;
  min-width:18px;height:18px;padding:0 5px;
  background:#ef4444;color:#fff;
  font-size:11px;font-weight:700;line-height:1;
  border-radius:999px;margin-left:6px;
  vertical-align:middle;
  box-shadow:0 1px 3px rgba(239,68,68,.35);
}
.task-circle{position:relative}
.task-circle-dot{
  position:absolute;top:-4px;right:-4px;
  background:#ef4444;color:#fff;
  font-size:10px;font-weight:700;line-height:1;
  min-width:16px;height:16px;padding:0 4px;
  border-radius:999px;
  display:flex;align-items:center;justify-content:center;
  border:2px solid #fff;
  box-shadow:0 1px 3px rgba(239,68,68,.4);
  pointer-events:none;
}

/* ── Nút "Báo cáo" của HS (cạnh program tab nav) ───────────────────── */
.hs-report-btn {
  display:inline-flex; align-items:center; gap:6px;
  background: linear-gradient(135deg,#0ea5e9 0%,#2563eb 100%);
  color:#fff; border:0;
  padding:9px 16px; border-radius:12px;
  font-weight:700; font-size:13px;
  cursor:pointer;
  box-shadow:0 6px 18px rgba(37,99,235,.28);
  white-space:nowrap;
  transition: transform .12s ease, box-shadow .12s ease, filter .12s ease;
}
.hs-report-btn:hover { transform: translateY(-1px); box-shadow:0 10px 22px rgba(37,99,235,.32); filter: brightness(1.05); }
.hs-report-btn:active { transform: translateY(0); }
.hs-report-btn[disabled] { opacity:.6; cursor:not-allowed; }
@media (max-width: 520px) {
  .hs-report-btn { padding:8px 12px; font-size:12.5px; }
}

/* ================================================================
   v2.0 — SIDEBAR LAYOUT (HS)
   Topbar + hero cũ ẨN trên desktop. Sidebar trái 260px cố định.
   ================================================================ */
.app-shell {
  display: grid;
  grid-template-columns: 260px 1fr;
  min-height: 100vh;
}
/* Ẩn topbar + hero cũ (vẫn giữ DOM nếu code khác tham chiếu sẽ không lỗi vì các ID đã chuyển vào sidebar) */
body > .topbar { display: none !important; }
.hero-section { display: none !important; }
.program-row { display: none !important; }
/* mobile topbar */
.mobile-topbar {
  display: none;
  align-items: center;
  gap: 12px;
  padding: 10px 14px;
  background: var(--bg-card);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 90;
  box-shadow: 0 1px 3px rgba(67,56,202,.06);
}
.mobile-topbar .brand-mini {
  font-weight: 700;
  font-size: 14.5px;
  color: var(--text);
  flex: 1;
  letter-spacing: -.01em;
}
.hamburger-btn {
  background: var(--primary-light);
  color: var(--primary);
  border: 1px solid var(--border);
  border-radius: 10px;
  width: 38px; height: 38px;
  font-size: 18px; line-height: 1;
  cursor: pointer;
  font-weight: 700;
}
.hamburger-btn:hover { background: var(--primary-soft); }

.sidebar-backdrop {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.45);
  z-index: 99;
  backdrop-filter: blur(2px);
}
.sidebar-backdrop.open { display: block; }

/* ==== Sidebar HS ==== */
.hs-sidebar {
  background: var(--bg-card);
  border-right: 1px solid var(--border);
  padding: 18px 14px 16px;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 4px;
  box-shadow: 1px 0 8px rgba(67,56,202,.04);
}
.hs-sidebar::-webkit-scrollbar { width: 6px; }
.hs-sidebar::-webkit-scrollbar-thumb { background: var(--border); border-radius: 99px; }

.sb-brand {
  display: flex; align-items: center; gap: 10px;
  padding: 4px 8px 14px;
  border-bottom: 1px solid var(--border-soft);
  margin-bottom: 12px;
}
.sb-brand img, .sb-brand svg {
  width: 40px; height: 40px; border-radius: 10px; flex-shrink: 0;
}
.sb-brand-text {
  font-weight: 800; font-size: 14px; color: var(--text);
  letter-spacing: -.01em; line-height: 1.2;
}
.sb-brand-text small {
  display: block; font-size: 9.5px; color: var(--text-muted);
  font-weight: 600; margin-top: 3px; letter-spacing: .08em;
}

.sb-user-card {
  display: flex; align-items: center; gap: 10px;
  background: var(--bg-soft);
  border: 1px solid var(--border-soft);
  border-radius: 12px;
  padding: 10px 12px;
  margin-bottom: 12px;
}
.sb-user-avatar {
  width: 40px; height: 40px; border-radius: 11px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-size: 18px; font-weight: 700; flex-shrink: 0;
  box-shadow: 0 4px 12px rgba(79,70,229,.25);
}
.sb-user-info { flex: 1; min-width: 0; }
.sb-user-info strong {
  display: block; font-size: 13px; font-weight: 700; color: var(--text);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.sb-user-info small {
  display: block; font-size: 11px; color: var(--text-muted); margin-top: 1px;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}

/* Stats card gradient (giữ tinh thần hero cũ) */
.sb-stats-card {
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  border-radius: 14px;
  padding: 14px;
  margin-bottom: 14px;
  color: #fff;
  box-shadow: 0 8px 20px rgba(79,70,229,.22);
}
.sb-stats-row {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 6px;
}
.sb-stats-title {
  font-size: 10.5px; font-weight: 700; letter-spacing: .08em; opacity: .95;
}
.sb-stats-value {
  font-size: 13px; font-weight: 800; letter-spacing: -.01em;
}
.sb-stats-card .stat-bar-track {
  background: rgba(255,255,255,0.22); height: 6px; border-radius: 99px;
}
.sb-stats-card .stat-bar-fill {
  background: #fff; height: 100%; border-radius: 99px; transition: width .4s;
}
.sb-stats-card .stat-bar-gradient {
  /* Gradient liên tục: trắng -> xanh nhạt -> xanh đậm -> tím (tương ứng tier 1-4) */
  background: linear-gradient(90deg, #FFFFFF 0%, #BBF7D0 33%, #16A34A 66%, #7C3AED 100%);
  height: 8px; border-radius: 99px; position: relative; margin-top: 4px;
  box-shadow: inset 0 0 0 1px rgba(255,255,255,.4);
}
.sb-stats-card .seg-marker {
  position: absolute; top: 50%; width: 16px; height: 16px;
  background: var(--marker-color, #fff);
  border: 2.5px solid #fff;
  border-radius: 50%; transform: translate(-50%, -50%);
  box-shadow: 0 2px 8px rgba(0,0,0,.3);
  transition: left .4s, background .3s;
}
.sb-stats-card .seg-marker.hidden { opacity: 0; }
.sb-stats-tagline {
  font-size: 11.5px; opacity: .92; margin-top: 9px; line-height: 1.4;
}

.sb-nav-section {
  font-size: 10px; font-weight: 800; color: var(--text-muted);
  text-transform: uppercase; letter-spacing: .12em;
  padding: 12px 8px 6px;
}
.sb-nav { display: flex; flex-direction: column; gap: 3px; }
.sb-nav-sub { padding-left: 14px; }
.sb-nav-sub:empty { display: none; }

/* Re-style các button cũ thành nav item dọc trong sidebar */
.sb-nav .program-tab-btn,
.sb-nav .tab-btn {
  display: flex !important;
  align-items: center;
  gap: 8px;
  width: 100%;
  text-align: left;
  background: var(--primary-light);
  border: 0;
  color: var(--text);
  font-weight: 600;
  font-size: 13.5px;
  padding: 9px 11px;
  border-radius: 9px;
  cursor: pointer;
  font-family: inherit;
  letter-spacing: -.005em;
  transition: background .12s ease, color .12s ease;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  box-shadow: none;
  min-width: 0;
}
.sb-nav .program-tab-btn:hover,
.sb-nav .tab-btn:hover {
  background: var(--primary-light);
  color: var(--primary-dark);
}
/* Program (cha): nền cố định, không đổi khi click — chỉ vai trò toggle expand */
.sb-nav .program-tab-btn {
  background: var(--primary-light) !important;
  color: var(--text) !important;
  font-weight: 700 !important;
  box-shadow: none !important;
}
.sb-nav .program-tab-btn:hover { background: var(--primary-soft) !important; }
.sb-prog-toggle-inline {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 16px;
  font-size: 9px;
  color: var(--text-muted);
  flex-shrink: 0;
  margin-right: 2px;
}
/* Course (con) active: nền trắng + dải tím bên trái — phân cấp nhẹ hơn cha */
.sb-courses-for-program .tab-btn.active {
  background: #fff;
  color: var(--primary-dark);
  font-weight: 700;
  box-shadow: inset 3px 0 0 var(--primary);
}
.sb-nav-sub .tab-btn { font-size: 12.5px; padding: 7px 11px; }
/* v2.0.13 — breadcrumb vị trí HS đang xem */
.hs-breadcrumb {
  font-size: 13.5px; color: var(--text-soft); font-weight: 500;
  margin: 0 0 14px; padding: 0;
  background: transparent; border-radius: 0;
  display: flex; align-items: center; gap: 7px; flex-wrap: wrap;
}
.hs-breadcrumb b { color: #eaf0fb; font-weight: 700; }
.hs-breadcrumb .bc-mut { color: #9fb0d9; }
.hs-breadcrumb .bc-sep { color: #4b5b7a; font-size: 15px; }
.hs-breadcrumb .bc-ico { display:inline-flex; align-items:center; justify-content:center; width:28px; height:28px; border-radius:9px; background:rgba(103,232,249,.14); color:#67e8f9; }
.hs-breadcrumb .sep { color: var(--text-muted); }
/* v2.0.12 — chevron inline trong button program; program button = toggle */

/* v2.0.8 — khóa con flatten + no border-left phụ */
.sb-courses-for-program {
  padding-left: 16px;
  border-left: 0;
  margin: 1px 0 6px 0;
  display: flex;
  flex-direction: column;
  gap: 1px;
}
.sb-courses-for-program:empty { display: none; }
.sb-courses-for-program .tab-btn {
  font-size: 11.5px;
  padding: 5px 9px;
  font-weight: 500;
  color: var(--text-muted);
  background: transparent;
}
.sb-courses-for-program .tab-btn:hover { color: var(--primary-dark); background: var(--bg-section); }
.sb-nav .program-tab-btn .program-tab-name,
.sb-nav .tab-btn { flex: 1; min-width: 0; }
.sb-nav .badge {
  margin-left: auto; font-size: 10px; font-weight: 700;
  background: rgba(0,0,0,.06); color: var(--text-soft);
  padding: 2px 7px; border-radius: 99px;
}
.sb-nav .program-tab-btn.active .badge,
.sb-nav .tab-btn.active .badge {
  background: rgba(255,255,255,.2); color: #fff;
}

.sb-bottom {
  margin-top: auto;
  padding-top: 12px;
  border-top: 1px solid var(--border-soft);
  display: flex; flex-direction: column; gap: 4px;
}
.sb-action-btn {
  display: flex; align-items: center; gap: 9px;
  width: 100%; text-align: left;
  background: transparent; border: 0;
  color: var(--text-soft); font-weight: 600; font-size: 13px;
  padding: 9px 11px; border-radius: 9px;
  cursor: pointer; font-family: inherit; text-decoration: none;
  transition: background .12s ease, color .12s ease;
}
.sb-action-btn:hover { background: var(--primary-light); color: var(--primary-dark); }
.sb-action-btn[disabled] { opacity: .5; cursor: not-allowed; }
.sb-action-btn span { font-size: 15px; }
.sb-action-btn.sb-logout { color: var(--danger); }
.sb-action-btn.sb-logout:hover { background: #FEE2E2; color: var(--danger); }

/* Main area */
.hs-main {
  min-width: 0;
  overflow-x: clip;   /* dùng clip thay hidden để KHÔNG tạo scroll context, sticky vẫn hoạt động */
  padding: 18px 28px 60px;
}
.hs-main .page-container {
  max-width: 100%;
  padding: 0;
  margin: 0;
}

/* ==== Mobile (< 900px) ==== */
@media (max-width: 900px) {
  .app-shell { grid-template-columns: 1fr; }
  .mobile-topbar { display: flex; }
  .hs-sidebar {
    position: fixed;
    left: -290px;
    top: 0;
    width: 280px;
    height: 100vh;
    z-index: 100;
    transition: left .25s ease;
    box-shadow: 8px 0 24px rgba(0,0,0,.15);
  }
  .hs-sidebar.open { left: 0; }
  .hs-main { padding: 14px 14px 60px; }
}
@media (min-width: 901px) {
  .mobile-topbar { display: none !important; }
  .sidebar-backdrop { display: none !important; }
}

/* ============== Topbar sticky HS main (breadcrumb trái + bell phải) ============== */
.hs-breadcrumb { margin-right: auto; }
.hs-sim-btn {
  display: inline-flex; align-items: center; gap: 6px;
  appearance: none; border: none; cursor: pointer; font-family: inherit;
  text-decoration: none; background: linear-gradient(135deg,#3b82f6,#6366f1); color: #fff;
  font-weight: 700; font-size: 13px; height: 38px; padding: 0 16px; border-radius: 99px; white-space: nowrap;
  box-shadow: 0 2px 8px rgba(59,130,246,.32); transition: transform .12s, box-shadow .12s, filter .12s;
}
.hs-sim-btn:hover { transform: translateY(-1px); box-shadow: 0 4px 14px rgba(59,130,246,.45); filter: brightness(1.06); }
.hs-topbar-sticky {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 0;
  margin-bottom: 8px;
  background: rgba(8,12,26,.55);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid rgba(255,255,255,.08);
}
.hs-topbar-sticky .hs-breadcrumb { margin: 0; flex: 1; min-width: 0; }
.hs-topbar-actions {
  display: flex; justify-content: flex-end;
  margin-bottom: 8px;
}
.notif-wrap { position: relative; display: inline-block; }
.notif-bell {
  position: relative;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 9px;
  cursor: pointer;
  font-size: 18px; line-height: 1;
  padding: 7px 11px;
  color: var(--text);
  transition: background .15s, border-color .15s;
  box-shadow: 0 1px 3px rgba(15,23,42,.06);
}
.notif-bell:hover { background: var(--primary-light); border-color: var(--primary); }
.notif-badge {
  position: absolute; top: -4px; right: -4px;
  background: #ef4444; color: #fff;
  font-size: 10px; font-weight: 800;
  min-width: 18px; height: 18px; padding: 0 5px;
  border-radius: 99px;
  display: inline-flex; align-items: center; justify-content: center;
  border: 2px solid #fff;
  box-shadow: 0 1px 3px rgba(239,68,68,.4);
}
.notif-panel {
  position: absolute; top: calc(100% + 8px); right: 0;
  width: 380px; max-width: 95vw; max-height: 480px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: 0 10px 32px rgba(15,23,42,.18), 0 2px 6px rgba(15,23,42,.08);
  z-index: 2000;
  display: flex; flex-direction: column;
  overflow: hidden;
}
.notif-panel[hidden] { display: none !important; }
.notif-head {
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 14px;
  border-bottom: 1px solid var(--border);
  background: #f8fafc;
}
.notif-head strong { font-size: 14px; color: var(--text); }
.notif-mark-all {
  background: transparent; border: 0; cursor: pointer;
  color: var(--primary); font-size: 11.5px; font-weight: 600;
  padding: 4px 8px; border-radius: 6px;
}
.notif-mark-all:hover { background: var(--primary-light); }
.notif-list {
  overflow-y: auto; flex: 1;
  display: flex; flex-direction: column;
}
.notif-item {
  display: flex; gap: 8px; align-items: flex-start;
  padding: 10px 12px;
  border-bottom: 1px solid #f1f5f9;
  transition: background .12s;
}
.notif-item:hover { background: #f8fafc; }
.notif-item.unread { background: #f0f9ff; }
.notif-item.unread:hover { background: #e0f2fe; }
.notif-item:last-child { border-bottom: 0; }
.notif-content { flex: 1; min-width: 0; cursor: pointer; }
.notif-del {
  background: #fef3c7;
  border: 1px solid #fbbf24;
  cursor: pointer;
  font-size: 13px; line-height: 1;
  padding: 4px 7px; border-radius: 6px;
  color: #d97706;
  flex-shrink: 0;
  transition: background .15s, color .15s, border-color .15s;
}
.notif-del:hover {
  background: #f59e0b;
  border-color: #d97706;
  color: #fff;
}
.notif-title { font-size: 12.5px; font-weight: 600; color: var(--text); line-height: 1.35; }
.notif-body  { font-size: 11.5px; color: var(--text-soft); margin-top: 2px; line-height: 1.4; }
.notif-time  { font-size: 10.5px; color: #94a3b8; margin-top: 4px; }
.notif-empty { text-align: center; padding: 32px 16px; color: #94a3b8; font-style: italic; font-size: 13px; }
@media (max-width: 640px) { .notif-panel { width: calc(100vw - 24px); } }

/* ============== Tier 0-10 chia 4 nhóm hiển thị ============== */
.hs-tier-circle {
  display: inline-flex; align-items: center; justify-content: center;
  width: 24px; height: 24px; border-radius: 50%;
  font-weight: 800; font-size: 11.5px; line-height: 1;
  flex-shrink: 0;
}
.hs-tier-circle.tier-g0 { background: #f1f5f9; border: 1.5px dashed #94a3b8; color: #94a3b8; }
.hs-tier-circle.tier-g1 { background: #fff;    border: 1.5px solid #22C55E; color: #16a34a; }
.hs-tier-circle.tier-g2 { background: #86EFAC; border: 1.5px solid #86EFAC; color: #14532d; }
.hs-tier-circle.tier-g3 { background: #16A34A; border: 1.5px solid #15803D; color: #fff; }
.hs-tier-circle.tier-g4 { background: #A78BFA; border: 1.5px solid #7C3AED; color: #fff; box-shadow: 0 0 8px rgba(167,139,250,.55); }
.tier-groups-grid { display: flex; flex-direction: column; gap: 6px; margin: 8px 0 12px; }
.tier-group {
  background: #f8fafc; border: 1px solid #e2e8f0;
  border-radius: 9px; padding: 7px 10px;
  display: grid; grid-template-columns: 100px 1fr auto;
  align-items: center; gap: 10px;
}
.tier-group-label { font-size: 12px; font-weight: 700; color: #334155; letter-spacing: -.005em; }
.tier-group-desc { font-size: 10.5px; color: #64748b; font-style: italic; text-align: right; white-space: nowrap; }
.tier-group-buttons { display: flex; gap: 5px; flex-wrap: wrap; }
.tier-btn {
  width: 30px; height: 30px; border-radius: 50%;
  font-weight: 800; font-size: 12.5px; line-height: 1;
  cursor: pointer; font-family: inherit;
  transition: transform .12s, box-shadow .12s, background .12s;
  display: inline-flex; align-items: center; justify-content: center;
}
.tier-btn:hover { transform: scale(1.08); }
.tier-group.tier-g1 .tier-btn { background: #fff;    border: 1.5px solid #22C55E; color: #16a34a; }
.tier-group.tier-g2 .tier-btn { background: #86EFAC; border: 1.5px solid #86EFAC; color: #14532d; }
.tier-group.tier-g3 .tier-btn { background: #16A34A; border: 1.5px solid #15803D; color: #fff; }
.tier-group.tier-g4 .tier-btn { background: #A78BFA; border: 1.5px solid #7C3AED; color: #fff; box-shadow: 0 0 8px rgba(167,139,250,.45); }
.tier-btn.active { transform: scale(1.15); }
.tier-group.tier-g1 .tier-btn.active { box-shadow: 0 0 0 3px #fff, 0 0 0 5px #22C55E, 0 4px 12px rgba(34,197,94,.25); }
.tier-group.tier-g2 .tier-btn.active { box-shadow: 0 0 0 3px #fff, 0 0 0 5px #16A34A, 0 4px 12px rgba(34,197,94,.25); }
.tier-group.tier-g3 .tier-btn.active { box-shadow: 0 0 0 3px #fff, 0 0 0 5px #14532D, 0 4px 12px rgba(20,83,45,.3); }
.tier-group.tier-g4 .tier-btn.active { box-shadow: 0 0 0 3px #fff, 0 0 0 5px #7C3AED, 0 6px 16px rgba(124,58,237,.4); }
@media (max-width: 640px) {
  .tier-group { grid-template-columns: 1fr auto; }
  .tier-group-label { margin-bottom: 0; }
  .tier-group-desc { grid-column: 1 / -1; text-align: left; }
}

/* ====================================================== */
/* v2.0.35 — HS sidebar áp dụng pattern GV (dark + sky)    */
/* ====================================================== */
.hs-sidebar {
  background: #0f172a;                /* slate-900 */
  border-right: 1px solid #1e293b;
  padding: 0 0 12px 0;
  color: #cbd5e1;
  gap: 0;
  box-shadow: none;
}
.hs-sidebar::-webkit-scrollbar-thumb { background: #334155; }

/* Brand: logo + 2 dòng tiêu đề */
.hs-sidebar .sb-brand {
  background: transparent;
  border-bottom: 1px solid #1e293b;
  margin-bottom: 0;
  padding: 20px 18px;
  justify-content: flex-start;
  gap: 12px;
}
.hs-sidebar .sb-brand img, .hs-sidebar .sb-brand svg {
  width: 36px; height: 36px; border-radius: 8px; flex-shrink: 0;
}
.hs-sidebar .sb-brand-text {
  color: #f1f5f9;
  font-size: 13px; font-weight: 700;
  text-align: left; letter-spacing: -.005em; line-height: 1.2;
}
.hs-sidebar .sb-brand-text small {
  color: #38bdf8;
  font-weight: 700; font-size: 8.5px;
  letter-spacing: .14em; margin-top: 3px;
}

/* User card */
.hs-sidebar .sb-user-card {
  background: #1e293b;
  border: 1px solid #334155;
  margin: 12px;
  border-radius: 10px;
}
.hs-sidebar .sb-user-avatar {
  background: linear-gradient(135deg, #0ea5e9, #06b6d4);
  box-shadow: 0 4px 12px rgba(14,165,233,.3);
  color: #fff;
}
.hs-sidebar .sb-user-info strong { color: #f1f5f9; }
.hs-sidebar .sb-user-info small { color: #94a3b8; }
.hs-sidebar .sb-user-tags {
  display: flex; flex-wrap: wrap; gap: 3px 4px;
  margin-top: 5px;
}
.hs-sidebar .sb-user-tag {
  display: inline-block;
  font-size: 9.5px; font-weight: 600;
  padding: 2px 6px; border-radius: 5px;
  white-space: nowrap;
  background: rgba(14,165,233,.18); color: #7dd3fc;
}
.hs-sidebar .sb-user-tag.prog { background: rgba(56,189,248,.18); color: #7dd3fc; }
.hs-sidebar .sb-user-tag.class { background: rgba(34,197,94,.18); color: #86efac; }
.hs-sidebar .sb-user-tag.class.online { background: rgba(250,204,21,.18); color: #fde047; }

/* Stats card (Tiến trình + Cấp độ) — slate-800 wrapper, vẫn giữ gradient bar */
.hs-sidebar .sb-stats-card {
  background: #1e293b;
  border: 1px solid #334155;
  margin: 0 12px 12px;
  border-radius: 10px;
  padding: 12px 14px;
}
.hs-sidebar .sb-stats-card .sb-stats-title { color: #94a3b8; font-size: 9.5px; font-weight: 700; letter-spacing: .08em; }
.hs-sidebar .sb-stats-card .sb-stats-value { color: #f1f5f9; font-weight: 700; font-size: 11px; }
.hs-sidebar .sb-stats-card .sb-stats-tagline { color: #cbd5e1; margin-top: 7px; font-size: 10.5px; }
.hs-sidebar .sb-stats-card .stat-bar-track { background: #334155; }

/* Section header */
.hs-sidebar .sb-nav-section {
  color: #64748b;
  padding: 14px 18px 6px;
  font-size: 10px; font-weight: 700;
  letter-spacing: .14em;
  text-transform: uppercase;
}

/* Nav wrapper */
.hs-sidebar .sb-nav { padding: 0 8px; gap: 4px; }

/* CẤP 2 — program-tab-btn (Robotics/Scratch): card style giống GV cấp 2 */
.hs-sidebar .program-tab-btn {
  position: relative;
  display: flex !important;
  align-items: center;
  gap: 8px;
  width: 100%;
  text-align: left;
  background: rgba(30, 41, 59, .55) !important;
  border: 1px solid rgba(51, 65, 85, .5) !important;
  border-radius: 7px !important;
  color: #e2e8f0 !important;
  font-weight: 600 !important;
  font-size: 11.5px !important;
  padding: 7px 12px 7px 24px !important;
  cursor: pointer;
  box-shadow: none !important;
  font-family: inherit;
  transition: background .12s, border-color .12s, color .12s;
}
.hs-sidebar .program-tab-btn::before {
  content: '';
  position: absolute; left: 12px; top: 50%;
  width: 6px; height: 6px;
  border-radius: 50%;
  background: #475569;
  transform: translateY(-50%);
  transition: background .12s ease;
}
.hs-sidebar .program-tab-btn:hover {
  background: #1e293b !important;
  border-color: #475569 !important;
  color: #f1f5f9 !important;
}
.hs-sidebar .program-tab-btn .sb-prog-toggle-inline { display: none !important; }

/* Khi nested mở (theo class .expanded gắn bởi JS) hoặc khi có program active */
.hs-sidebar .program-tab-btn.expanded {
  background: rgba(30, 41, 59, .9) !important;
  border-color: #475569 !important;
  color: #f1f5f9 !important;
}
.hs-sidebar .program-tab-btn.expanded::before,
.hs-sidebar .program-tab-btn.active::before { background: #0ea5e9; }
.hs-sidebar .program-tab-btn.active {
  background: rgba(14, 165, 233, .22) !important;
  border-color: #0ea5e9 !important;
  color: #7dd3fc !important;
  box-shadow: 0 0 0 1px #0ea5e9, 0 4px 12px rgba(14,165,233,.18) !important;
}

/* CẤP 3 wrapper — vạch dọc tree-guide */
.hs-sidebar .sb-courses-for-program {
  position: relative;
  padding: 4px 0 4px 16px;
  margin: 0 0 4px;
}
.hs-sidebar .sb-courses-for-program::before {
  content: '';
  position: absolute;
  left: 6px; top: 6px; bottom: 6px;
  width: 2px;
  background: #334155;
  border-radius: 2px;
}
.hs-sidebar .sb-courses-for-program:empty { display: none; }

/* CẤP 3 — course tab-btn (Cơ bản/Nâng cao): card style, font mảnh */
.hs-sidebar .sb-courses-for-program .tab-btn {
  display: flex !important;
  align-items: center;
  gap: 8px;
  width: 100%;
  text-align: left;
  background: rgba(30, 41, 59, .55) !important;
  border: 1px solid rgba(51, 65, 85, .5) !important;
  border-radius: 7px !important;
  color: #cbd5e1 !important;
  font-weight: 400 !important;
  font-size: 11px !important;
  padding: 6px 10px !important;
  margin: 2px 0;
  cursor: pointer;
  font-family: inherit;
  transition: background .12s, border-color .12s, color .12s;
  box-shadow: none !important;
}
.hs-sidebar .sb-courses-for-program .tab-btn:hover {
  background: #1e293b !important;
  border-color: #475569 !important;
  color: #f1f5f9 !important;
}
.hs-sidebar .sb-courses-for-program .tab-btn.active {
  background: rgba(14, 165, 233, .22) !important;
  border-color: #0ea5e9 !important;
  color: #7dd3fc !important;
  font-weight: 500 !important;
  box-shadow: 0 0 0 1px #0ea5e9, 0 4px 12px rgba(14,165,233,.18) !important;
}

/* Badge (số bài/nhiệm vụ) */
.hs-sidebar .sb-nav .badge {
  background: #334155;
  color: #cbd5e1;
  font-size: 9px;
  font-weight: 800;
  padding: 2px 7px;
  border-radius: 99px;
  margin-left: auto;
}
.hs-sidebar .sb-courses-for-program .tab-btn.active .badge {
  background: #0ea5e9;
  color: #fff;
  box-shadow: 0 2px 6px rgba(14,165,233,.4);
}

/* Bottom: actions Báo cáo / Hình ảnh / Thoát */
.hs-sidebar .sb-bottom {
  border-top: 1px solid #1e293b;
  padding: 12px;
  gap: 6px;
  margin-top: auto;
}
.hs-sidebar .sb-action-btn {
  background: rgba(30, 41, 59, .55);
  border: 1px solid rgba(51, 65, 85, .5);
  color: #cbd5e1;
  border-radius: 7px;
  padding: 8px 11px;
  font-weight: 600;
  font-size: 12px;
}
.hs-sidebar .sb-action-btn:hover {
  background: #1e293b;
  border-color: #475569;
  color: #f1f5f9;
}
.hs-sidebar .sb-action-btn[disabled] { opacity: .4; }
.hs-sidebar .sb-action-btn.sb-logout {
  color: #fca5a5;
  border-color: rgba(244,63,94,.25);
}
.hs-sidebar .sb-action-btn.sb-logout:hover {
  background: rgba(244,63,94,.15);
  color: #fda4af;
  border-color: rgba(244,63,94,.5);
}

/* Breadcrumb (main) — dùng style giống GV */
.hs-main .hs-breadcrumb {
  color: #9fb0d9;
}

/* ====================================================================
   Giao diện học v3: Chủ đề (tab) → Bài (danh sách thu gọn) → Nhiệm vụ (thẻ)
   ==================================================================== */
/* Màu thương hiệu LẤY ĐÚNG TỪ giaoducstem.com/assets/css/main.css */
:root{--hs-accent:#C01428;--hs-accent-dark:#a01020;--hs-accent-soft:#fdf2f3;--hs-navy:#17375E;--hs-logo-red:#E4223B;--hs-blue:#0078ae}

/* === GIAO DIỆN SÁNG — khu bài học === */
/* Tab nối khung */
.hs-topic-tabs{display:flex;gap:6px;flex-wrap:wrap;margin:0;padding:0 0 0 4px;position:relative;z-index:2}
.hs-topic-tab{appearance:none;cursor:pointer;font-size:13px;font-weight:600;color:#64748b;background:#eef1f4;border:1px solid #e5e7eb;border-bottom:none;border-radius:12px 12px 0 0;padding:9px 18px;margin-bottom:-1px;display:inline-flex;align-items:center;gap:6px;transition:color .15s,background .15s}
.hs-topic-tab:hover:not(.active){color:var(--hs-accent);background:#e9edf1}
.hs-topic-tab.active{background:#fff;color:var(--hs-accent-dark);border-color:#e5e7eb;border-bottom:1px solid #fff;position:relative;z-index:3}
.hs-topic-tab-dot{color:#16a34a;font-size:12px}
.hs-topic-panel{border:1px solid #e5e7eb;border-radius:14px;padding:18px 18px 16px;position:relative;z-index:1;color:#1f2937;background:#fff;box-shadow:0 1px 4px rgba(15,23,42,.05)}

/* Tiêu đề chủ đề */
.hs-topic-head{display:flex;align-items:center;justify-content:space-between;gap:10px;margin:2px 0 16px;flex-wrap:wrap}
.hs-topic-head-title{font-size:18px;font-weight:700;color:var(--hs-navy);letter-spacing:normal;position:relative;padding-left:13px}
.hs-topic-head-title::before{content:"";position:absolute;left:0;top:50%;transform:translateY(-50%);width:4px;height:20px;background:var(--hs-navy);border-radius:2px}
.hs-topic-head-meta{font-size:11px;font-weight:600;color:var(--hs-navy);background:#eef2f7;padding:4px 10px;border-radius:999px}

/* Bài — nền thay đường kẻ */
.hs-lessons{display:flex;flex-direction:column;gap:10px}
.hs-lesson{border-radius:14px;transition:box-shadow .15s,background .15s}
.hs-lesson:not(.collapsed){background:#fff;box-shadow:0 4px 18px rgba(15,23,42,.08)}
.hs-lesson-head{display:flex;align-items:center;justify-content:space-between;gap:10px;padding:12px 14px;cursor:pointer;user-select:none;border-radius:14px;transition:background .15s}
.hs-lesson.collapsed .hs-lesson-head{background:#f5f7f9}
.hs-lesson.collapsed .hs-lesson-head:hover{background:#eceff3}
.hs-lesson-head-left{display:flex;align-items:center;gap:10px;min-width:0}
.hs-lesson-caret{appearance:none;border:none;background:rgba(15,23,42,.06);color:#94a3b8;cursor:pointer;width:22px;height:22px;display:flex;align-items:center;justify-content:center;transition:transform .2s ease,color .15s,background .15s;padding:0;flex:0 0 auto;border-radius:7px}
.hs-lesson-caret svg{display:block}
.hs-lesson:not(.collapsed) .hs-lesson-caret{transform:rotate(90deg);color:var(--hs-accent);background:var(--hs-accent-soft)}
.hs-lesson-name{font-size:14.5px;font-weight:700;color:#0f172a;letter-spacing:normal;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.hs-lesson-head-right{display:flex;align-items:center;gap:12px;flex:0 0 auto}
.hs-lesson-count{font-size:11.5px;font-weight:600;color:#64748b}
.hs-lesson-noeval{font-size:12px;color:#94a3b8}
.hs-lesson-body{padding:0 12px 10px}
.hs-lesson.collapsed .hs-lesson-body{display:none}
.hs-lesson-desc{font-size:12.5px;color:#64748b;line-height:1.55;margin:10px 0 0}

/* Nhiệm vụ — robot V3 trên nền sáng */
.hs-task-cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:10px;margin-top:16px}
.hs-task-card{text-align:center;padding:6px 6px 12px;border-radius:18px;cursor:pointer;transition:transform .15s,background .15s}
.hs-task-card:hover{transform:translateY(-3px);background:rgba(15,23,42,.03)}
.hs-tc-stars{height:18px;margin-bottom:6px}
.hs-tc-img{position:relative;width:100%;aspect-ratio:16/9;border-radius:14px;overflow:hidden;background:transparent}
.hs-tc-img img{width:100%;height:100%;object-fit:contain;object-position:center;display:block;transition:transform .22s ease}
.hs-task-card:hover .hs-tc-img img{transform:scale(1.06)}
.hs-task-card.is-todo .hs-tc-img{opacity:.55}
.hs-task-card.is-todo .hs-tc-name{color:#94a3b8}
.hs-task-card.is-todo:hover .hs-tc-img{opacity:1}
/* Hoạt ảnh nhẹ (KHÔNG chuyển động liên tục): thẻ hiện dần khi mở chủ đề */
@keyframes hsCardIn{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}
.hs-task-card{animation:hsCardIn .4s ease backwards}
.hs-task-card:nth-child(2){animation-delay:.05s}
.hs-task-card:nth-child(3){animation-delay:.1s}
.hs-task-card:nth-child(4){animation-delay:.15s}
.hs-task-card:nth-child(5){animation-delay:.2s}
.hs-task-card:nth-child(n+6){animation-delay:.25s}
@media (prefers-reduced-motion:reduce){
  .hs-task-card:hover .hs-tc-img img{transform:none}
  .hs-task-card{animation:none}
}
.hs-tc-lock{position:absolute;top:6px;right:6px;width:24px;height:24px;border-radius:50%;background:rgba(15,23,42,.55);color:#fff;font-size:13px;display:flex;align-items:center;justify-content:center;-webkit-backdrop-filter:blur(2px);backdrop-filter:blur(2px)}
.hs-task-card .hs-tc-name{font-size:12.5px;font-weight:600;color:#1e293b;margin-top:5px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}

.hs-stars{position:relative;display:inline-block;font-size:13.5px;line-height:1;white-space:nowrap;letter-spacing:1px}
.hs-stars-bg{color:#dfe3e8}
.hs-stars-fg{position:absolute;left:0;top:0;overflow:hidden;color:#f59e0b;white-space:nowrap;letter-spacing:1px}
.hs-empty{font-size:13px;color:#94a3b8;font-style:italic;padding:10px 0}

/* ====================================================================
   HEADER NGANG TRẮNG (kiểu giaoducstem.com): menu chính=chương trình, con=khóa
   ==================================================================== */
.hs-topnav{position:sticky;top:0;z-index:60;background:#fff;border-bottom:1px solid #eef0f3;box-shadow:0 1px 6px rgba(15,23,42,.05)}
.hs-topnav-top{display:flex;align-items:center;justify-content:space-between;gap:14px;padding:10px 22px;max-width:1320px;margin:0 auto;flex-wrap:wrap}
.hs-topnav-menu{border-top:1px solid #eef0f3;background:#fff}
.hs-brand-wrap{display:flex;align-items:center}
.hs-nav-brand{display:flex;align-items:center;gap:12px;text-decoration:none;flex:0 0 auto}
.hs-nav-brand img{border-radius:8px;display:block;width:56px;height:auto}
.hs-brand-tx{display:inline-flex;flex-direction:column;align-items:center;line-height:1.15}
.hs-brand-tx b{font-size:20px;font-weight:800;color:var(--hs-blue);letter-spacing:-.3px;white-space:nowrap}
.hs-brand-tx b i{color:var(--hs-logo-red);font-style:normal}
.hs-brand-tx small{font-size:11px;font-weight:400;color:var(--text-muted);letter-spacing:.3px;margin-top:3px}
.hs-header-date-sep{padding-left:18px;margin-left:18px;border-left:1px solid var(--border)}
.hs-header-date{font-size:13px;color:var(--text-muted);white-space:nowrap}
@media (max-width:760px){.hs-header-date-sep{display:none}}
.hs-prognav{display:flex;gap:4px;justify-content:center;flex-wrap:wrap;padding:4px 22px;max-width:1320px;margin:0 auto}
.hs-prog-btn{appearance:none;border:none;background:transparent;color:var(--hs-navy);font-weight:600;font-size:13px;height:36px;padding:0 15px;display:inline-flex;align-items:center;border-radius:6px;cursor:pointer;transition:color .15s,background .15s}
.hs-prog-btn:hover{color:var(--hs-accent);background:rgba(192,20,40,.07)}
.hs-prog-btn.active{color:#fff;background:var(--hs-accent);font-weight:700}
.hs-prog-btn.active:hover{color:#fff;background:var(--hs-accent-dark)}
.hs-nav-right{display:flex;align-items:center;gap:10px;flex:0 0 auto;position:relative}
.hs-topnav .notif-wrap{margin-right:0}
.hs-topnav .notif-bell{width:38px;height:38px;padding:0;display:inline-flex;align-items:center;justify-content:center;font-size:18px;border-radius:99px;background:#f1f5f9;border:1px solid #e2e8f0;color:#475569;box-shadow:none}
.hs-topnav .notif-bell:hover{background:#e9edf2;border-color:#e2e8f0}
.hs-profile-btn{display:flex;align-items:center;gap:8px;background:#f1f5f9;border:1px solid #e2e8f0;border-radius:99px;padding:4px 12px 4px 4px;cursor:pointer;color:#1f2937}
.hs-profile-btn:hover{background:#e9edf2}
.hs-profile-av{width:30px;height:30px;border-radius:50%;overflow:hidden;display:inline-flex;align-items:center;justify-content:center;background:#e2e8f0;font-size:16px;flex:0 0 auto}
.hs-profile-av img{width:100%;height:100%;object-fit:cover}
.hs-profile-name{font-size:13px;font-weight:600;max-width:130px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.hs-profile-caret{color:#94a3b8;font-size:11px}
.hs-profile-menu{position:absolute;right:0;top:calc(100% + 10px);width:300px;background:#fff;border:1px solid #e5e7eb;border-radius:14px;box-shadow:0 18px 44px rgba(15,23,42,.18);padding:14px;z-index:70}
.hs-profile-menu[hidden]{display:none}
.hs-pm-head{display:flex;align-items:center;gap:10px;margin-bottom:12px}
.hs-pm-user{min-width:0}
.hs-pm-user strong{display:block;color:#0f172a;font-size:14px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.hs-pm-user small{color:#64748b;font-size:12px}
.hs-pm-stats{background:#f8fafc;border:1px solid #eef1f4;border-radius:11px;padding:11px 12px}
.hs-pm-stats .sb-stats-row{display:flex;justify-content:space-between;align-items:center;font-size:11.5px}
.hs-pm-stats .sb-stats-title{color:#64748b;font-weight:700}
.hs-pm-stats #progress-text{color:#0f172a;font-weight:700;font-size:12px}
.hs-pm-stats .sb-stats-tagline{font-size:11.5px;color:#64748b;margin-top:8px;line-height:1.45}
.hs-pm-actions{display:flex;flex-direction:column;gap:2px;margin-top:12px;border-top:1px solid #eef1f4;padding-top:10px}
.hs-pm-actions button,.hs-pm-actions a{display:flex;align-items:center;gap:9px;background:transparent;border:none;color:#334155;font-size:13.5px;font-weight:600;padding:9px 10px;border-radius:9px;cursor:pointer;text-decoration:none;text-align:left;font-family:inherit}
.hs-pm-actions button:hover,.hs-pm-actions a:hover{background:#f1f5f9}
.hs-pm-actions button:disabled{opacity:.45;cursor:not-allowed}
.hs-pm-actions .hs-pm-logout{color:#dc2626}
.hs-pm-actions .hs-pm-logout:hover{background:#fef2f2}

/* Dropdown khóa con dưới mỗi chương trình (giống gd-nav-sub của giaoducstem.com) */
.hs-nav-item{position:relative;display:inline-flex}
.hs-nav-item.has-sub > .hs-prog-btn::after{content:'▾';font-size:10px;margin-left:5px;opacity:.6}
.hs-nav-sub{display:none;position:absolute;top:100%;left:50%;transform:translateX(-50%);min-width:200px;background:#fff;border:1px solid #e8e8e8;border-top:3px solid var(--hs-accent);border-radius:0 0 8px 8px;box-shadow:0 8px 22px rgba(0,0,0,.13);padding:6px 0;z-index:1100}
.hs-nav-item:hover .hs-nav-sub{display:block}
.hs-nav-sub-link{display:block;width:100%;text-align:left;appearance:none;border:none;background:none;padding:9px 16px;font-size:13.5px;font-weight:500;color:#333;cursor:pointer;white-space:nowrap;border-bottom:1px solid #f4f4f4;font-family:inherit;transition:color .12s,background .12s}
.hs-nav-sub-link:last-child{border-bottom:none}
.hs-nav-sub-link:hover{color:var(--hs-accent);background:#fdf2f3}
.hs-nav-sub-link.active{color:var(--hs-accent);font-weight:700}

.hs-main-full{max-width:1320px;margin:0 auto;padding:20px 22px 60px}

/* THÂN: sidebar Mục lục (trái) + khung chính (phải) */
.hs-body{display:flex;gap:20px;max-width:1320px;margin:0 auto;padding:18px 22px 60px;align-items:flex-start}
.hs-body .hs-main{flex:1;min-width:0;padding:0}
.hs-toc{width:268px;flex:0 0 auto;background:#fff;border:1px solid #e8eaee;border-radius:14px;padding:12px 10px;position:sticky;top:120px;box-shadow:0 1px 4px rgba(15,23,42,.05)}
.hs-toc-title{font-size:11px;font-weight:800;letter-spacing:.07em;color:#94a3b8;text-transform:uppercase;padding:4px 10px 10px}
.hs-toc-course{margin-bottom:8px}
.hs-toc-course-name{display:flex;align-items:center;gap:10px;font-size:13.5px;font-weight:800;letter-spacing:.02em;color:var(--hs-navy);padding:9px 6px 7px;text-align:center}
.hs-toc-course-name::before,.hs-toc-course-name::after{content:"";flex:1;height:1px;background:linear-gradient(90deg,transparent,#cdd6e2)}
.hs-toc-course-name::after{background:linear-gradient(90deg,#cdd6e2,transparent)}
.hs-toc-topics{list-style:none;margin:0;padding:0}
.hs-toc-topic{font-size:13px;color:#475569;padding:8px 12px;border-radius:8px;cursor:pointer;line-height:1.45;border-left:2px solid transparent;transition:background .12s,color .12s}
.hs-toc-topic:hover{background:#f6f8fa;color:var(--hs-accent)}
.hs-toc-topic.active{background:var(--hs-accent-soft);color:var(--hs-accent-dark);font-weight:700;border-left-color:var(--hs-accent)}
.hs-toc-no{font-weight:800;color:var(--hs-navy)}
.hs-toc-topic.active .hs-toc-no{color:var(--hs-accent-dark)}
.hs-toc-empty,.hs-toc-empty-sm{font-size:12.5px;color:#94a3b8;padding:8px 10px;font-style:italic}
@media (max-width:860px){
  .hs-body{flex-direction:column;padding:14px 14px 50px;gap:14px}
  .hs-toc{width:100%;position:static}
}
@media (max-width:760px){
  .hs-topnav-top{gap:10px;padding:8px 12px}
  .hs-profile-name{display:none}
  .hs-prognav{padding-left:12px;padding-right:12px}
}

/* Nút Đăng nhập (khách) + Popup đăng nhập */
.hs-login-btn{appearance:none;border:none;background:var(--hs-accent);color:#fff;font-weight:700;font-size:13px;padding:8px 18px;border-radius:8px;cursor:pointer;transition:background .15s}
.hs-login-btn:hover{background:var(--hs-accent-dark)}
.hs-login-modal{max-width:380px;width:92%;text-align:center;padding:26px 26px 22px;position:relative;border-radius:16px}
.hs-login-head{margin-bottom:14px}
.hs-login-logo{border-radius:12px;margin-bottom:8px}
.hs-login-modal h2{font-size:22px;font-weight:800;color:#0f172a;margin:0 0 4px}
.hs-login-head p{font-size:13.5px;color:#64748b;margin:0}
.hs-login-err{margin-bottom:12px;padding:10px 14px;background:#fee2e2;color:#dc2626;border-radius:9px;font-size:13.5px;font-weight:500;text-align:left}
.hs-login-field{text-align:left;margin-bottom:12px}
.hs-login-field label{display:block;font-size:11px;font-weight:700;color:#64748b;letter-spacing:.04em;margin-bottom:5px}
.hs-login-field input{width:100%;padding:11px 13px;border:1px solid #cbd5e1;border-radius:9px;font-size:14px;font-family:inherit}
.hs-login-field input:focus{outline:none;border-color:var(--hs-accent);box-shadow:0 0 0 3px rgba(192,20,40,.12)}
.hs-login-submit{width:100%;appearance:none;border:none;background:var(--hs-accent);color:#fff;font-weight:700;font-size:15px;padding:12px;border-radius:10px;cursor:pointer;margin-top:4px;transition:background .15s}
.hs-login-submit:hover{background:var(--hs-accent-dark)}
.hs-login-submit:disabled{opacity:.6;cursor:default}
.hs-login-foot{font-size:12.5px;color:#94a3b8;margin:14px 0 0}

/* Chương trình bị khóa (chưa đăng nhập / chưa được gán) → nội dung xám + banner */
.hs-lock-banner{background:#fff7ed;border:1px solid #fed7aa;color:#9a3412;font-size:13px;font-weight:600;padding:11px 14px;border-radius:10px;margin-bottom:14px;display:flex;align-items:center;gap:8px;line-height:1.5}
.hs-locked-panel{filter:grayscale(1);opacity:.6}
#hs-toc.hs-locked{filter:grayscale(1);opacity:.72}

/* ====================================================================
   GIAO DIỆN TỐI — phong cách dunglailaptrinh.com (nền #06060a + glow),
   ĐỔI ACCENT cam → XANH DƯƠNG logo. Bật bằng [data-theme="dark"] trên <html>.
   ==================================================================== */
[data-theme="dark"]{
  --bg:#06060a;--bg-soft:#0d1017;--bg-section:#151a23;--bg-card:#11151d;
  --border:rgba(255,255,255,.09);--border-soft:rgba(255,255,255,.06);
  --text:#eef2f8;--text-soft:#a6b2c4;--text-muted:#6b7787;
  --hs-accent:#0ea5e9;--hs-accent-dark:#0284c7;--hs-accent-soft:rgba(14,165,233,.16);
  --hs-navy:#cfe0f0;--hs-blue:#38bdf8;--hs-logo-red:#ff6275;
  color-scheme:dark;
}
[data-theme="dark"] body{
  background:
    radial-gradient(ellipse 1100px 560px at 12% -5%, rgba(14,165,233,.16) 0%, transparent 55%),
    radial-gradient(ellipse 900px 520px at 100% 100%, rgba(2,132,199,.10) 0%, transparent 55%),
    #06060a;
  color:var(--text);
}
/* Header */
[data-theme="dark"] .hs-topnav{background:rgba(8,10,15,.92);backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px);border-bottom-color:rgba(255,255,255,.07);box-shadow:0 1px 0 rgba(255,255,255,.03)}
[data-theme="dark"] .hs-topnav-menu{background:transparent;border-top-color:rgba(255,255,255,.06)}
[data-theme="dark"] .hs-brand-tx small{color:#8a97a8}
[data-theme="dark"] .hs-prog-btn{color:#cfd9e6}
[data-theme="dark"] .hs-prog-btn:hover{color:#7dd3fc;background:rgba(14,165,233,.12)}
[data-theme="dark"] .hs-prog-btn.active,[data-theme="dark"] .hs-prog-btn.active:hover{color:#fff;background:linear-gradient(135deg,#0ea5e9,#0284c7);box-shadow:0 4px 16px rgba(14,165,233,.35)}
/* Khối nút bên phải */
[data-theme="dark"] .hs-profile-btn,[data-theme="dark"] .hs-topnav .notif-bell{background:rgba(255,255,255,.05);border-color:rgba(255,255,255,.1);color:#e7edf5}
[data-theme="dark"] .hs-profile-btn:hover{background:rgba(255,255,255,.09)}
[data-theme="dark"] .hs-profile-av{background:rgba(255,255,255,.08)}
[data-theme="dark"] .hs-profile-caret{color:#7a8696}
[data-theme="dark"] .hs-profile-menu{background:#0e1219;border-color:rgba(255,255,255,.1);box-shadow:0 18px 50px rgba(0,0,0,.6)}
[data-theme="dark"] .hs-pm-user strong,[data-theme="dark"] .hs-pm-stats #progress-text{color:#eef2f8}
[data-theme="dark"] .hs-pm-user small,[data-theme="dark"] .hs-pm-stats .sb-stats-title,[data-theme="dark"] .hs-pm-stats .sb-stats-tagline{color:#9aa6b6}
[data-theme="dark"] .hs-pm-stats{background:rgba(255,255,255,.04);border-color:rgba(255,255,255,.07)}
[data-theme="dark"] .hs-pm-actions{border-top-color:rgba(255,255,255,.08)}
[data-theme="dark"] .hs-pm-actions button,[data-theme="dark"] .hs-pm-actions a{color:#cdd6e2}
[data-theme="dark"] .hs-pm-actions button:hover,[data-theme="dark"] .hs-pm-actions a:hover{background:rgba(255,255,255,.06)}
[data-theme="dark"] .hs-pm-actions .hs-pm-logout{color:#ff6275}
[data-theme="dark"] .hs-pm-actions .hs-pm-logout:hover{background:rgba(255,98,117,.12)}
/* Sidebar Mục lục */
[data-theme="dark"] .hs-toc{background:rgba(255,255,255,.035);border-color:rgba(255,255,255,.08);box-shadow:0 1px 0 rgba(255,255,255,.03)}
[data-theme="dark"] .hs-toc-title{color:#6b7787}
[data-theme="dark"] .hs-toc-course-name{color:#cfe0f0}
[data-theme="dark"] .hs-toc-course-name::before{background:linear-gradient(90deg,transparent,rgba(255,255,255,.18))}
[data-theme="dark"] .hs-toc-course-name::after{background:linear-gradient(90deg,rgba(255,255,255,.18),transparent)}
[data-theme="dark"] .hs-toc-topic{color:#a6b2c4}
[data-theme="dark"] .hs-toc-topic:hover{background:rgba(255,255,255,.05);color:#7dd3fc}
[data-theme="dark"] .hs-toc-topic.active{background:rgba(14,165,233,.16);color:#7dd3fc;border-left-color:#0ea5e9}
[data-theme="dark"] .hs-toc-no{color:#cfe0f0}
[data-theme="dark"] .hs-toc-topic.active .hs-toc-no{color:#7dd3fc}
[data-theme="dark"] .hs-toc-empty,[data-theme="dark"] .hs-toc-empty-sm{color:#6b7787}
/* Tabs + panel chủ đề */
[data-theme="dark"] .hs-topic-tab{background:rgba(255,255,255,.04);border-color:rgba(255,255,255,.08);color:#9aa6b6}
[data-theme="dark"] .hs-topic-tab:hover:not(.active){background:rgba(255,255,255,.07);color:#7dd3fc}
[data-theme="dark"] .hs-topic-tab.active{background:#11151d;color:#7dd3fc;border-color:rgba(255,255,255,.08);border-bottom-color:#11151d}
[data-theme="dark"] .hs-topic-panel{background:rgba(255,255,255,.035);border-color:rgba(255,255,255,.08);color:#dbe3ee;box-shadow:none}
[data-theme="dark"] .hs-topic-head-title{color:#eaf2fb}
[data-theme="dark"] .hs-topic-head-title::before{background:#0ea5e9}
[data-theme="dark"] .hs-topic-head-meta{background:rgba(14,165,233,.14);color:#9fcde8}
/* Bài học */
[data-theme="dark"] .hs-lesson:not(.collapsed){background:rgba(255,255,255,.05);box-shadow:0 8px 26px rgba(0,0,0,.45)}
[data-theme="dark"] .hs-lesson.collapsed .hs-lesson-head{background:rgba(255,255,255,.035)}
[data-theme="dark"] .hs-lesson.collapsed .hs-lesson-head:hover{background:rgba(255,255,255,.06)}
[data-theme="dark"] .hs-lesson-name{color:#eef2f8}
[data-theme="dark"] .hs-lesson-count{color:#9aa6b6}
[data-theme="dark"] .hs-lesson-desc{color:#a6b2c4}
[data-theme="dark"] .hs-lesson-noeval{color:#6b7787}
[data-theme="dark"] .hs-lesson-caret{background:rgba(255,255,255,.08);color:#9aa6b6}
[data-theme="dark"] .hs-lesson:not(.collapsed) .hs-lesson-caret{background:rgba(14,165,233,.18);color:#7dd3fc}
/* Nhiệm vụ (robot) */
[data-theme="dark"] .hs-task-card:hover{background:rgba(255,255,255,.05)}
[data-theme="dark"] .hs-task-card .hs-tc-name{color:#cdd6e2}
[data-theme="dark"] .hs-tc-img{background:transparent;box-shadow:none}
[data-theme="dark"] .hs-stars-bg{color:#3a4350}
[data-theme="dark"] .hs-empty{color:#6b7787}
/* Banner khóa */
[data-theme="dark"] .hs-lock-banner{background:rgba(255,165,0,.08);border-color:rgba(255,165,0,.25);color:#f3c98a}
/* Đăng nhập (nút + popup) */
[data-theme="dark"] .hs-login-btn,[data-theme="dark"] .hs-login-submit{background:linear-gradient(135deg,#0ea5e9,#0284c7);box-shadow:0 4px 16px rgba(14,165,233,.35)}
[data-theme="dark"] .hs-login-btn:hover,[data-theme="dark"] .hs-login-submit:hover{background:linear-gradient(135deg,#38bdf8,#0ea5e9)}
[data-theme="dark"] .hs-login-modal h2{color:#eef2f8}
[data-theme="dark"] .hs-login-head p,[data-theme="dark"] .hs-login-foot{color:#9aa6b6}
[data-theme="dark"] .hs-login-field label{color:#9aa6b6}
[data-theme="dark"] .hs-login-field input{background:rgba(255,255,255,.05);border-color:rgba(255,255,255,.14);color:#eef2f8}
[data-theme="dark"] .hs-login-field input:focus{border-color:#0ea5e9;box-shadow:0 0 0 3px rgba(14,165,233,.25)}
[data-theme="dark"] .hs-login-err{background:rgba(255,98,117,.12);color:#ff8a98}

/* Nút đổi giao diện (header phải) */
.hs-theme-btn{appearance:none;width:38px;height:38px;border-radius:99px;border:1px solid #e2e8f0;background:#f1f5f9;color:#475569;cursor:pointer;display:inline-flex;align-items:center;justify-content:center;flex:0 0 auto;transition:background .15s,color .15s,border-color .15s}
.hs-theme-btn:hover{background:#e9edf2}
.hs-theme-btn svg{display:block}
.hs-theme-btn .ic-sun{display:none}
.hs-theme-btn .ic-moon{display:block}
[data-theme="dark"] .hs-theme-btn{background:rgba(255,255,255,.06);border-color:rgba(255,255,255,.13);color:#ffd76a}
[data-theme="dark"] .hs-theme-btn:hover{background:rgba(255,255,255,.1)}
[data-theme="dark"] .hs-theme-btn .ic-sun{display:block}
[data-theme="dark"] .hs-theme-btn .ic-moon{display:none}

/* Hàng menu: chương trình (trái) + nút Sa bàn ảo / đổi giao diện (phải) */
.hs-menu-row{display:flex;align-items:center;justify-content:space-between;gap:14px;max-width:1320px;margin:0 auto;padding:4px 22px}
.hs-menu-row .hs-prognav{margin:0;padding:0;max-width:none;flex:1 1 auto}
.hs-menu-actions{display:flex;align-items:center;gap:10px;flex:0 0 auto}
@media (max-width:760px){.hs-menu-row{padding-left:12px;padding-right:12px;flex-wrap:wrap;gap:8px}.hs-menu-actions{margin-left:auto}}