/*
 * TapLai Frontend — Material Design 3 Edition
 * Design System: #2563eb primary, Roboto, Material Symbols Outlined
 * Elevation: 5-level shadow system per M3 spec
 */

/* ===== DESIGN TOKENS ===== */
.tl-app {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #dbeafe;
    --primary-glow: rgba(37,99,235,.12);
    --on-primary: #ffffff;
    --success: #10b981;
    --success-bg: #d1fae5;
    --danger: #ef4444;
    --danger-bg: #fee2e2;
    --warning: #f59e0b;
    --warning-bg: #fef3c7;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-disabled: #94a3b8;
    --surface: #ffffff;
    --surface-variant: #f8fafc;
    --outline: #e2e8f0;
    --outline-variant: #f1f5f9;
    /* Material elevation system */
    --elevation-1: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.06);
    --elevation-2: 0 4px 8px -1px rgba(0,0,0,.08), 0 2px 4px -2px rgba(0,0,0,.04);
    --elevation-3: 0 10px 24px -4px rgba(0,0,0,.1), 0 4px 8px -2px rgba(0,0,0,.04);
    --elevation-4: 0 20px 48px -8px rgba(0,0,0,.12), 0 8px 16px -4px rgba(0,0,0,.06);
    --elevation-5: 0 32px 64px -12px rgba(0,0,0,.15), 0 12px 24px -4px rgba(0,0,0,.08);
    /* Surfaces */
    --radius-xs: 8px;
    --radius-sm: 12px;
    --radius-md: 16px;
    --radius-lg: 24px;
    --transition: .2s cubic-bezier(.4,0,.2,1);
    --transition-fast: .15s cubic-bezier(.4,0,.2,1);
}

/* ===== BASE ===== */
.tl-app {
    font-family: 'Roboto', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    color: var(--text-primary);
    line-height: 1.6;
    max-width: 1100px;
    margin: 0 auto;
    padding: 24px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}
.tl-app *, .tl-app *::before, .tl-app *::after { box-sizing: border-box; }

/* Material Symbols icon sizing */
.tl-app .material-symbols-outlined {
    font-size: 18px;
    vertical-align: middle;
    margin-right: 2px;
    font-variation-settings: 'FILL' 0, 'wght' 400, 'GRAD' 0, 'opsz' 20;
}

.tl-section { animation: tlSlideUp .35s cubic-bezier(.16,1,.3,1); }
@keyframes tlSlideUp {
    from { opacity: 0; transform: translateY(12px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ===== HEADER ===== */
.tl-header { margin-bottom: 24px; }
.tl-title {
    font-size: 24px; font-weight: 700; color: var(--text-primary);
    margin: 0 0 6px; letter-spacing: -.02em;
}
.tl-subtitle { font-size: 14px; color: var(--text-secondary); margin: 0; line-height: 1.5; }
.tl-back-btn {
    display: inline-flex; align-items: center; gap: 6px;
    background: none; border: none; color: var(--text-secondary); cursor: pointer;
    font-size: 14px; font-weight: 500; padding: 8px 0; margin-bottom: 4px;
    font-family: inherit; transition: color var(--transition);
}
.tl-back-btn:hover { color: var(--primary); }
.tl-back-btn .material-symbols-outlined { font-size: 16px; }

/* ===== SHOW/HIDE BY DEVICE ===== */
.tl-mobile-only { display: none !important; }
.tl-desktop-only { display: flex !important; }

/* ===== FILTER BAR (Row 1) ===== */
.tl-filter-bar {
    display: flex; align-items: center; gap: 8px; margin-bottom: 12px;
}
.tl-filter-buttons {
    flex: 1;
    min-width: 0;
    display: flex !important;
    flex-wrap: nowrap !important;
    gap: 8px;
    overflow-x: auto !important;
    overflow-y: hidden !important;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    -ms-overflow-style: none;
    padding-bottom: 2px;
}
.tl-filter-buttons::-webkit-scrollbar { display: none; }

/* Search toggle icon button */
.tl-search-toggle {
    display: flex; align-items: center; justify-content: center;
    width: 42px; height: 42px; border-radius: 50%;
    border: 2px solid var(--outline); background: var(--surface);
    cursor: pointer; transition: all var(--transition);
    color: var(--text-secondary); flex-shrink: 0;
    font-family: inherit;
}
.tl-search-toggle .material-symbols-outlined { font-size: 20px; margin: 0; }
.tl-search-toggle:hover { border-color: var(--primary); color: var(--primary); box-shadow: var(--elevation-2); }
.tl-search-toggle.active {
    background: var(--primary); color: var(--on-primary);
    border-color: var(--primary); box-shadow: 0 2px 8px rgba(37,99,235,.25);
}

/* Mobile select — full reset from Flatsome */
.tl-category-select {
    flex: 1; min-width: 0;
    padding: 10px 32px 10px 12px !important;
    border: 2px solid var(--outline) !important;
    border-radius: 12px !important;
    font-size: 14px !important; font-family: inherit !important;
    color: var(--text-primary) !important;
    background-color: var(--surface) !important;
    outline: none !important; cursor: pointer;
    height: auto !important; line-height: 1.4 !important;
    box-shadow: none !important;
    -webkit-appearance: none !important; appearance: none !important;
    background-image: url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' width='20' height='20' viewBox='0 0 24 24' fill='%23475569'%3E%3Cpath d='M7 10l5 5 5-5z'/%3E%3C/svg%3E") !important;
    background-repeat: no-repeat !important;
    background-position: right 8px center !important;
    background-size: 18px !important;
    margin-bottom: 0 !important;
}
.tl-category-select:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px var(--primary-glow);
}

/* ===== SEARCH BAR (Row 2, hidden by default) ===== */
.tl-search-bar {
    display: none; align-items: center; gap: 8px;
    margin-bottom: 16px; position: relative;
}
.tl-search-bar.open { display: flex; }
.tl-search-bar-icon {
    position: absolute; left: 12px; top: 50%; transform: translateY(-50%);
    font-size: 18px; color: var(--text-disabled); pointer-events: none;
}
.tl-search-bar .tl-search-input {
    flex: 1; padding: 10px 40px 10px 40px;
    border: 2px solid var(--outline); border-radius: 12px;
    font-size: 14px; font-family: inherit; color: var(--text-primary);
    background: var(--surface); outline: none;
    transition: border-color var(--transition), box-shadow var(--transition);
}
.tl-search-bar .tl-search-input::placeholder { color: var(--text-disabled); }
.tl-search-bar .tl-search-input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px var(--primary-glow);
}
.tl-search-close {
    position: absolute; right: 8px; top: 50%; transform: translateY(-50%);
    display: flex; align-items: center; justify-content: center;
    width: 28px; height: 28px; border-radius: 50%;
    border: none; background: var(--outline-variant);
    cursor: pointer; color: var(--text-secondary);
    transition: all var(--transition-fast);
}
.tl-search-close .material-symbols-outlined { font-size: 16px; margin: 0; }
.tl-search-close:hover { background: var(--outline); color: var(--text-primary); }

/* ===== HẠNG SELECTION ===== */
.tl-hang-grid {
    display: grid; grid-template-columns: repeat(auto-fill, minmax(190px, 1fr));
    gap: 16px;
}
.tl-hang-card {
    position: relative;
    background: var(--surface); border: 2px solid var(--outline); border-radius: var(--radius-lg);
    padding: 28px 16px 24px; cursor: pointer; text-align: center;
    transition: all var(--transition); font-family: inherit;
    box-shadow: var(--elevation-1);
    overflow: hidden;
}
.tl-hang-card::before {
    content: ''; position: absolute; top: 0; left: 0; right: 0; height: 4px;
    background: linear-gradient(90deg, var(--primary), #60a5fa);
    opacity: 0; transition: opacity var(--transition);
}
.tl-hang-card:hover {
    border-color: var(--primary-light);
    box-shadow: var(--elevation-3);
    transform: translateY(-4px);
}
.tl-hang-card:hover::before { opacity: 1; }
.tl-hang-badge {
    display: inline-flex; align-items: center; justify-content: center;
    width: 56px; height: 56px; border-radius: var(--radius-md);
    background: linear-gradient(135deg, var(--primary), #3b82f6);
    color: var(--on-primary); font-size: 20px; font-weight: 700;
    margin-bottom: 12px; box-shadow: 0 4px 12px rgba(37,99,235,.3);
}
.tl-hang-name {
    font-size: 15px; font-weight: 600; color: var(--text-primary);
    margin-bottom: 10px; text-transform: uppercase; letter-spacing: .03em;
}
.tl-hang-info {
    font-size: 12px; color: var(--text-disabled);
    display: flex; gap: 10px; justify-content: center; flex-wrap: wrap;
}
.tl-hang-info .material-symbols-outlined { font-size: 16px; color: var(--primary); }

/* ===== EXAM SET GRID ===== */
.tl-exam-grid {
    display: grid; grid-template-columns: repeat(auto-fill, minmax(155px, 1fr));
    gap: 12px;
}
.tl-exam-card {
    background: var(--surface); border: 2px solid var(--outline);
    border-radius: var(--radius-sm); padding: 20px 14px;
    cursor: pointer; text-align: center;
    transition: all var(--transition); font-family: inherit;
    box-shadow: var(--elevation-1);
}
.tl-exam-card:hover {
    border-color: var(--primary-light); box-shadow: var(--elevation-2);
    transform: translateY(-2px);
}
.tl-exam-card.is-random {
    border-color: var(--warning);
    background: linear-gradient(135deg, #fffbeb, #fef3c7);
}
.tl-exam-card.is-random:hover { box-shadow: var(--elevation-2), 0 0 0 3px rgba(245,158,11,.08); }
.tl-exam-card-title { font-size: 15px; font-weight: 700; color: var(--text-primary); margin-bottom: 4px; }
.tl-exam-card-title .material-symbols-outlined { font-size: 18px; color: var(--warning); }
.tl-exam-card-meta { font-size: 12px; color: var(--text-disabled); margin-bottom: 8px; }
.tl-exam-card-status { font-size: 11px; font-weight: 600; padding: 4px 12px; border-radius: 20px; display: inline-block; }
.tl-exam-card-status.not-done { color: var(--text-disabled); background: var(--outline-variant); }
.tl-exam-card-status.passed { color: #166534; background: var(--success-bg); }
.tl-exam-card-status.passed .material-symbols-outlined { font-size: 14px; color: #16a34a; }
.tl-exam-card-status.failed { color: #991b1b; background: var(--danger-bg); }
.tl-exam-card-status.failed .material-symbols-outlined { font-size: 14px; color: #dc2626; }

/* ===== EXAM HEADER ===== */
.tl-exam-header {
    background: linear-gradient(135deg, #1e40af, var(--primary), #3b82f6);
    color: var(--on-primary); border-radius: var(--radius-lg);
    padding: 18px 28px; margin-bottom: 24px;
    display: flex; flex-wrap: wrap; align-items: center;
    justify-content: space-between; gap: 14px;
    box-shadow: var(--elevation-3);
}
.tl-exam-meta { display: flex; align-items: center; gap: 16px; }
.tl-exam-meta .tl-back-btn { color: rgba(255,255,255,.75); }
.tl-exam-meta .tl-back-btn:hover { color: #fff; }
.tl-exam-label { font-size: 16px; font-weight: 700; letter-spacing: .01em; }
.tl-timer-bar { display: flex; align-items: center; gap: 14px; }
.tl-timer {
    font-size: 22px; font-weight: 700; font-variant-numeric: tabular-nums;
    min-width: 80px; text-align: center; text-shadow: 0 1px 2px rgba(0,0,0,.1);
}
.tl-timer .material-symbols-outlined { font-size: 20px; opacity: .8; }
.tl-timer.danger { color: #fbbf24; animation: tlPulse 1s infinite; }
@keyframes tlPulse { 0%,100% { opacity: 1; } 50% { opacity: .5; } }
.tl-progress-mini {
    width: 130px; height: 6px; background: rgba(255,255,255,.2);
    border-radius: 3px; overflow: hidden;
}
.tl-progress-mini-fill {
    height: 100%; background: #22c55e; border-radius: 3px;
    transition: width .5s linear;
}
.tl-progress-mini-fill.danger { background: #fbbf24; }
.tl-answered-count { font-size: 13px; opacity: .8; }

/* ===== 2-COLUMN LAYOUT ===== */
.tl-exam-body { display: flex; gap: 24px; align-items: flex-start; }
.tl-question-panel { flex: 1; min-width: 0; }
.tl-sidebar {
    width: 240px; flex-shrink: 0;
    position: sticky; top: 80px;
}

/* ===== QUESTION ===== */
.tl-q-header {
    display: flex; align-items: center; gap: 8px; flex-wrap: wrap;
    margin-bottom: 16px;
}
.tl-q-badge {
    background: linear-gradient(135deg, var(--primary), #3b82f6);
    color: var(--on-primary); font-size: 13px; font-weight: 700;
    padding: 6px 16px; border-radius: var(--radius-xs);
    box-shadow: 0 2px 8px rgba(37,99,235,.2);
}
.tl-q-cat-badge {
    background: var(--primary-light); color: var(--primary-dark);
    font-size: 12px; font-weight: 500;
    padding: 5px 12px; border-radius: var(--radius-xs);
}
.tl-q-cat-badge .material-symbols-outlined { font-size: 14px; color: var(--primary); }
.tl-q-diemliet-badge {
    background: var(--danger-bg); color: var(--danger);
    font-size: 12px; font-weight: 600;
    padding: 5px 12px; border-radius: var(--radius-xs);
}

.tl-q-text {
    font-size: 17px; font-weight: 500; line-height: 1.8;
    color: var(--text-primary); margin-bottom: 20px;
    background: var(--surface); padding: 24px 28px;
    border-radius: var(--radius-md); border: 1px solid var(--outline);
    box-shadow: var(--elevation-1);
}

.tl-q-image {
    display: block; max-width: 100%; max-height: 300px;
    margin: 0 auto 24px; border-radius: var(--radius-sm);
    border: 1px solid var(--outline); box-shadow: var(--elevation-1);
}

/* ===== ANSWERS ===== */
.tl-answers { display: flex; flex-direction: column; gap: 10px; margin-bottom: 20px; }
.tl-answer {
    display: flex; align-items: flex-start; gap: 14px;
    padding: 16px 20px; border: 2px solid var(--outline);
    border-radius: var(--radius-sm); cursor: pointer;
    transition: all var(--transition); background: var(--surface);
    font-size: 15px; line-height: 1.65;
    box-shadow: var(--elevation-1);
}
.tl-answer:hover:not(.disabled) {
    border-color: #93c5fd; background: #f0f7ff;
    box-shadow: var(--elevation-2);
    transform: translateX(4px);
}
.tl-answer.selected {
    border-color: var(--primary); background: var(--primary-light);
    box-shadow: 0 0 0 3px var(--primary-glow), var(--elevation-2);
}
.tl-answer.correct {
    border-color: var(--success); background: var(--success-bg);
    box-shadow: 0 0 0 3px rgba(16,185,129,.1);
    cursor: default;
}
.tl-answer.incorrect {
    border-color: var(--danger); background: var(--danger-bg);
    box-shadow: 0 0 0 3px rgba(239,68,68,.08);
    cursor: default;
}
.tl-answer.disabled { cursor: default; }

.tl-answer-num {
    display: flex; align-items: center; justify-content: center;
    width: 32px; height: 32px; border-radius: 50%;
    background: var(--outline-variant); color: var(--text-secondary);
    font-size: 13px; font-weight: 700; flex-shrink: 0;
    transition: all var(--transition);
}
.tl-answer.selected .tl-answer-num { background: var(--primary); color: var(--on-primary); }
.tl-answer.correct .tl-answer-num { background: var(--success); color: var(--on-primary); }
.tl-answer.incorrect .tl-answer-num { background: var(--danger); color: var(--on-primary); }

.tl-answer-text { flex: 1; padding-top: 4px; }
.tl-answer-icon {
    font-size: 16px; flex-shrink: 0;
    display: flex; align-items: center; margin-top: 5px;
}
.tl-answer-icon .material-symbols-outlined { font-size: 20px; margin-right: 0; }
.tl-answer.correct .tl-answer-icon { color: var(--success); }
.tl-answer.incorrect .tl-answer-icon { color: var(--danger); }

/* ===== EXPLANATION ===== */
.tl-explanation {
    background: linear-gradient(135deg, #fef3c7, #fffbeb);
    border-left: 4px solid var(--warning);
    padding: 18px 24px; border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    font-size: 14px; line-height: 1.8; color: #78350f;
    margin-bottom: 20px; animation: tlSlideUp .3s ease;
    box-shadow: var(--elevation-1);
}
.tl-explanation .material-symbols-outlined { font-size: 18px; color: var(--warning); }

/* ===== SIDEBAR QUESTION GRID ===== */
.tl-q-numbers {
    display: grid; grid-template-columns: repeat(5, 1fr); gap: 6px;
    padding: 16px; background: var(--surface);
    border: 1px solid var(--outline); border-radius: var(--radius-md);
    max-height: 420px; overflow-y: auto;
    box-shadow: var(--elevation-1);
}
.tl-q-num {
    display: flex; align-items: center; justify-content: center;
    width: 100%; aspect-ratio: 1; border-radius: var(--radius-xs);
    cursor: pointer; font-size: 12px; font-weight: 600;
    color: var(--text-secondary); background: var(--surface-variant);
    border: 1.5px solid var(--outline); transition: all var(--transition-fast);
}
.tl-q-num:hover { border-color: #93c5fd; background: #f0f7ff; }
.tl-q-num.active {
    background: var(--warning); color: var(--on-primary);
    border-color: var(--warning);
    box-shadow: 0 2px 8px rgba(245,158,11,.35);
}
.tl-q-num.answered { background: var(--primary); color: var(--on-primary); border-color: var(--primary); }
.tl-q-num.correct { background: var(--success); color: var(--on-primary); border-color: var(--success); }
.tl-q-num.incorrect { background: var(--danger); color: var(--on-primary); border-color: var(--danger); }
.tl-q-num.diem-liet { position: relative; }
.tl-q-num.diem-liet::after {
    content: '★'; position: absolute; top: -3px; right: 1px;
    font-size: 9px; color: var(--danger); font-weight: 700;
}

/* ===== SUBMIT ===== */
.tl-submit-btn {
    width: 100%; padding: 14px; margin-top: 14px;
    background: linear-gradient(135deg, #dc2626, #ef4444);
    color: var(--on-primary); border: none; border-radius: var(--radius-sm);
    font-size: 15px; font-weight: 700; cursor: pointer;
    font-family: inherit; transition: all var(--transition);
    box-shadow: 0 4px 14px rgba(220,38,38,.3);
    text-transform: uppercase; letter-spacing: .05em;
}
.tl-submit-btn:hover {
    background: linear-gradient(135deg, #b91c1c, #dc2626);
    transform: translateY(-1px);
    box-shadow: 0 6px 20px rgba(220,38,38,.35);
}
.tl-submit-btn .material-symbols-outlined { font-size: 20px; margin-right: 6px; vertical-align: middle; }

/* ===== NAV BUTTONS ===== */
.tl-nav-buttons { display: flex; justify-content: space-between; margin-top: 20px; gap: 12px; }
.tl-nav-btn {
    padding: 12px 28px; border: 2px solid var(--outline);
    border-radius: var(--radius-sm); font-size: 14px; font-weight: 600;
    cursor: pointer; background: var(--surface); color: var(--text-secondary);
    font-family: inherit; transition: all var(--transition);
    box-shadow: var(--elevation-1);
}
.tl-nav-btn .material-symbols-outlined { font-size: 18px; }
.tl-nav-btn:hover {
    border-color: var(--primary); color: var(--primary);
    box-shadow: var(--elevation-2);
}
.tl-nav-btn:last-child {
    background: linear-gradient(135deg, var(--primary), #3b82f6);
    color: var(--on-primary); border-color: transparent;
    box-shadow: 0 4px 14px rgba(37,99,235,.25);
}
.tl-nav-btn:last-child:hover {
    background: linear-gradient(135deg, var(--primary-dark), var(--primary));
    box-shadow: 0 6px 20px rgba(37,99,235,.3);
    transform: translateY(-1px);
}

/* ===== RESULT ===== */
.tl-result-card {
    text-align: center; padding: 48px 36px;
    background: var(--surface); border-radius: var(--radius-lg);
    border: 1px solid var(--outline);
    box-shadow: var(--elevation-4);
}
.tl-result-icon {
    font-size: 64px; margin-bottom: 16px;
    animation: tlBounce .6s cubic-bezier(.16,1,.3,1);
}
.tl-result-icon .material-symbols-outlined {
    font-size: 64px;
    font-variation-settings: 'FILL' 1, 'wght' 400, 'GRAD' 0, 'opsz' 48;
}
@keyframes tlBounce {
    0% { transform: scale(0) rotate(-12deg); }
    50% { transform: scale(1.15) rotate(0); }
    100% { transform: scale(1) rotate(0); }
}
.tl-result-title { font-size: 26px; font-weight: 700; margin-bottom: 8px; letter-spacing: -.01em; }
.tl-result-title.passed { color: var(--success); }
.tl-result-title.failed { color: var(--danger); }
.tl-result-score {
    font-size: 56px; font-weight: 700; margin-bottom: 20px;
    background: linear-gradient(135deg, var(--primary), #3b82f6);
    -webkit-background-clip: text; -webkit-text-fill-color: transparent;
    background-clip: text;
}
.tl-result-detail {
    display: flex; justify-content: center; gap: 28px;
    font-size: 14px; color: var(--text-secondary); flex-wrap: wrap;
}
.tl-result-detail .material-symbols-outlined { font-size: 16px; margin-right: 4px; }
.tl-result-diemliet {
    margin-top: 20px; padding: 14px 24px;
    background: var(--danger-bg); color: #991b1b;
    border-radius: var(--radius-sm); font-size: 14px; font-weight: 600;
    display: inline-block;
}
.tl-result-actions {
    display: flex; justify-content: center; gap: 12px;
    margin-top: 28px; flex-wrap: wrap;
}
.tl-btn {
    padding: 12px 24px; border-radius: var(--radius-sm); font-size: 14px;
    font-weight: 600; cursor: pointer; border: 2px solid transparent;
    font-family: inherit; transition: all var(--transition);
    box-shadow: var(--elevation-1);
}
.tl-btn .material-symbols-outlined { font-size: 18px; margin-right: 6px; }
.tl-btn-primary {
    background: linear-gradient(135deg, var(--primary), #3b82f6);
    color: var(--on-primary); box-shadow: 0 4px 14px rgba(37,99,235,.25);
}
.tl-btn-primary:hover { transform: translateY(-2px); box-shadow: 0 6px 20px rgba(37,99,235,.3); }
.tl-btn-secondary {
    background: linear-gradient(135deg, var(--warning), #fbbf24);
    color: var(--on-primary); box-shadow: 0 4px 14px rgba(245,158,11,.2);
}
.tl-btn-secondary:hover { transform: translateY(-2px); box-shadow: 0 6px 20px rgba(245,158,11,.25); }
.tl-btn-outline { background: var(--surface); color: var(--text-secondary); border-color: var(--outline); }
.tl-btn-outline:hover { border-color: var(--primary); color: var(--primary); transform: translateY(-2px); }

/* ===== FILTER BUTTONS (kept from original, bar defined above) ===== */
.tl-filter-btn {
    padding: 9px 18px; border: 2px solid var(--outline); border-radius: 24px;
    font-size: 13px; font-weight: 500; cursor: pointer;
    background: var(--surface); color: var(--text-secondary); font-family: inherit;
    transition: all var(--transition); box-shadow: var(--elevation-1);
    white-space: nowrap; flex-shrink: 0;
}
.tl-filter-btn .material-symbols-outlined { font-size: 16px; margin-right: 4px; }
.tl-filter-btn:hover {
    border-color: #93c5fd; color: var(--primary);
    box-shadow: var(--elevation-2);
}
.tl-filter-btn.active {
    background: linear-gradient(135deg, var(--primary), #3b82f6);
    color: var(--on-primary); border-color: transparent;
    box-shadow: 0 4px 14px rgba(37,99,235,.25);
}

/* ===== LEARN CONTAINER ===== */
.tl-learn-container { display: flex; gap: 24px; align-items: flex-start; }
.tl-learn-container .tl-question-panel { flex: 1; min-width: 0; }
.tl-learn-container .tl-sidebar { width: 240px; flex-shrink: 0; position: sticky; top: 80px; }

/* ===== EMPTY STATE ===== */
.tl-empty-state {
    text-align: center; padding: 48px 24px; color: var(--text-disabled);
    font-size: 16px; font-weight: 500;
    background: var(--surface-variant); border-radius: var(--radius-md);
    border: 2px dashed var(--outline);
}
.tl-empty-state .material-symbols-outlined { font-size: 24px; margin-right: 8px; color: var(--text-disabled); }

/* ===== CUSTOM CONFIRM MODAL (renders outside .tl-app, uses hardcoded values) ===== */
.tl-confirm-overlay {
    position: fixed; top: 0; left: 0; right: 0; bottom: 0; z-index: 999999;
    background: rgba(15,23,42,.55); backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    display: flex; align-items: center; justify-content: center;
    opacity: 0; transition: opacity .25s ease;
    font-family: 'Roboto', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    -webkit-font-smoothing: antialiased;
}
.tl-confirm-overlay.active { opacity: 1; }
.tl-confirm-card {
    background: #ffffff; border-radius: 24px;
    padding: 44px 40px 36px;
    max-width: 440px; width: 92%; text-align: center;
    box-shadow: 0 32px 64px -12px rgba(0,0,0,.18), 0 12px 24px -4px rgba(0,0,0,.1);
    transform: scale(.88) translateY(12px);
    transition: transform .3s cubic-bezier(.16,1,.3,1);
}
.tl-confirm-overlay.active .tl-confirm-card { transform: scale(1) translateY(0); }
.tl-confirm-icon {
    margin-bottom: 20px;
}
.tl-confirm-icon .material-symbols-outlined {
    font-size: 56px;
    font-variation-settings: 'FILL' 1, 'wght' 500, 'GRAD' 0, 'opsz' 48;
    color: #2563eb;
    display: block;
}
.tl-confirm-title {
    font-size: 22px; font-weight: 700; color: #0f172a;
    margin-bottom: 10px; letter-spacing: -.01em;
}
.tl-confirm-message {
    font-size: 15px; color: #475569; line-height: 1.7;
    margin-bottom: 32px;
}
.tl-confirm-actions { display: flex; gap: 12px; justify-content: center; }
.tl-confirm-btn {
    padding: 13px 36px; border-radius: 12px; font-size: 14px;
    font-weight: 600; cursor: pointer; border: 2px solid transparent;
    font-family: 'Roboto', sans-serif; transition: all .2s cubic-bezier(.4,0,.2,1);
    letter-spacing: .02em;
}
.tl-confirm-cancel {
    background: #f1f5f9; color: #475569;
    border-color: #e2e8f0;
}
.tl-confirm-cancel:hover { background: #e2e8f0; color: #0f172a; }
.tl-confirm-ok {
    background: linear-gradient(135deg, #2563eb, #3b82f6);
    color: #ffffff; box-shadow: 0 4px 16px rgba(37,99,235,.3);
}
.tl-confirm-ok:hover {
    box-shadow: 0 8px 24px rgba(37,99,235,.35);
    transform: translateY(-2px);
}
.tl-confirm-ok.danger {
    background: linear-gradient(135deg, #dc2626, #ef4444);
    box-shadow: 0 4px 16px rgba(220,38,38,.3);
}
.tl-confirm-ok.danger:hover { box-shadow: 0 8px 24px rgba(220,38,38,.35); }

/* ===== RESPONSIVE — TABLET (≤768px) ===== */
@media (max-width: 768px) {
    .tl-app { padding: 16px; }

    /* Show/hide swap */
    .tl-desktop-only { display: none !important; }
    .tl-mobile-only { display: flex !important; }

    /* Stack layout: question FIRST, sidebar below */
    .tl-exam-body, .tl-learn-container {
        flex-direction: column;
    }
    .tl-sidebar {
        width: 100% !important; position: static; order: 1;
    }
    .tl-question-panel { order: 0; }

    /* Collapsible question grid — compact on mobile */
    .tl-q-numbers {
        grid-template-columns: repeat(10, 1fr);
        max-height: 160px; overflow-y: auto;
        gap: 4px; padding: 10px;
    }
    .tl-q-num { font-size: 11px; border-radius: 6px; }

    /* Submit below grid */
    .tl-submit-btn { margin-top: 8px; padding: 12px; font-size: 14px; }

    /* Hạng grid — 2 columns */
    .tl-hang-grid { grid-template-columns: repeat(2, 1fr); gap: 10px; }
    .tl-hang-card { padding: 20px 12px 16px; border-radius: 16px; }
    .tl-hang-badge { width: 44px; height: 44px; font-size: 16px; border-radius: 12px; }
    .tl-hang-name { font-size: 13px; margin-bottom: 6px; }
    .tl-hang-info { font-size: 11px; gap: 6px; }

    /* Exam grid — 2 columns max */
    .tl-exam-grid { grid-template-columns: repeat(2, 1fr); gap: 8px; }
    .tl-exam-card { padding: 14px 10px; border-radius: 10px; }
    .tl-exam-card-title { font-size: 13px; }
    .tl-exam-card-meta { font-size: 11px; margin-bottom: 6px; }
    .tl-exam-card-status { font-size: 10px; padding: 3px 8px; }

    /* Exam header compact */
    .tl-exam-header {
        flex-direction: column; text-align: center;
        padding: 14px 16px; border-radius: 16px; gap: 10px;
    }
    .tl-exam-meta { flex-direction: column; gap: 6px; }
    .tl-timer { font-size: 20px; }
    .tl-progress-mini { width: 100%; }
    .tl-answered-count { font-size: 12px; }

    /* Question text */
    .tl-q-text { font-size: 15px; padding: 16px 18px; border-radius: 12px; }
    .tl-q-header { gap: 6px; margin-bottom: 12px; }
    .tl-q-badge { font-size: 12px; padding: 5px 12px; }
    .tl-q-cat-badge, .tl-q-diemliet-badge { font-size: 11px; padding: 4px 10px; }

    /* Answers — touch-friendly (min 44px) */
    .tl-answer { font-size: 14px; padding: 14px 14px; gap: 10px; border-radius: 10px; }
    .tl-answer-num { width: 28px; height: 28px; font-size: 12px; }
    .tl-answer:hover:not(.disabled) { transform: none; }

    /* Image */
    .tl-q-image { max-height: 200px; border-radius: 10px; }

    /* Explanation */
    .tl-explanation { padding: 14px 16px; font-size: 13px; }

    /* Nav — full width, sticky bottom feel */
    .tl-nav-buttons { gap: 8px; margin-top: 16px; }
    .tl-nav-btn { padding: 12px 16px; font-size: 13px; border-radius: 10px; flex: 1; text-align: center; }

    /* Filter bar compact */
    .tl-filter-buttons { gap: 6px; }
    .tl-filter-btn {
        white-space: nowrap; flex-shrink: 0;
        padding: 8px 14px; font-size: 12px; border-radius: 20px;
    }
    .tl-search-toggle { width: 38px; height: 38px; }
    .tl-search-bar .tl-search-input { font-size: 13px; }

    /* Result */
    .tl-result-card { padding: 32px 20px; border-radius: 16px; }
    .tl-result-icon .material-symbols-outlined { font-size: 48px; }
    .tl-result-title { font-size: 20px; }
    .tl-result-score { font-size: 40px; }
    .tl-result-detail { gap: 16px; font-size: 13px; }
    .tl-result-actions { flex-direction: column; gap: 8px; }
    .tl-btn { width: 100%; text-align: center; padding: 12px 20px; }

    /* Confirm modal */
    .tl-confirm-card { padding: 32px 24px 24px; border-radius: 20px; }
    .tl-confirm-icon .material-symbols-outlined { font-size: 44px; }
    .tl-confirm-title { font-size: 18px; }
    .tl-confirm-message { font-size: 14px; margin-bottom: 24px; }
    .tl-confirm-btn { padding: 12px 24px; }

    /* Header */
    .tl-title { font-size: 20px; }
    .tl-subtitle { font-size: 13px; }
    .tl-header { margin-bottom: 16px; }
    .tl-back-btn { font-size: 13px; }
}

/* ===== RESPONSIVE — SMALL PHONE (≤480px) ===== */
@media (max-width: 480px) {
    .tl-app { padding: 12px; }

    /* Single column */
    .tl-hang-grid { grid-template-columns: 1fr; gap: 8px; }
    .tl-hang-card { padding: 16px 12px 14px; }

    .tl-exam-grid { grid-template-columns: repeat(2, 1fr); gap: 6px; }

    /* Question grid tighter */
    .tl-q-numbers { grid-template-columns: repeat(6, 1fr); max-height: 300px; gap: 3px; padding: 8px; }

    /* Nav — keep on 1 row */
    .tl-nav-btn { font-size: 12px; padding: 10px 12px; }

    /* Confirm modal full width */
    .tl-confirm-actions { flex-direction: column; }
    .tl-confirm-btn { width: 100%; }

    /* Search at 480 */
    .tl-category-select { font-size: 12px; }

    /* Title */
    .tl-title { font-size: 18px; }

    /* Timer */
    .tl-timer { font-size: 18px; }

    /* Filter even more compact */
    .tl-filter-btn { padding: 6px 12px; font-size: 11px; }
}