/* ── Base ── */
*, *::before, *::after { box-sizing: border-box; }
body { overflow: hidden; }

.fade-in { animation: fadeIn 0.25s ease-out; }
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(8px); }
    to   { opacity: 1; transform: translateY(0); }
}

/* ── Sidebar ── */
.nav-link.active { background: #f1f5f9; color: #0f172a; font-weight: 600; }
.nav-link.active svg { color: #3b82f6; }

/* ── Option Buttons ── */
.option-btn {
    display: flex;
    align-items: flex-start;
    width: 100%;
    text-align: left;
    padding: 13px 16px;
    margin-bottom: 10px;
    border: 1.5px solid #e2e8f0;
    border-radius: 12px;
    background: #fff;
    font-size: 0.88rem;
    color: #334155;
    cursor: pointer;
    transition: border-color 0.15s, background 0.15s, box-shadow 0.15s;
    line-height: 1.5;
}
.option-btn:hover:not(:disabled) {
    border-color: #3b82f6;
    background: #eff6ff;
    box-shadow: 0 0 0 3px rgba(59,130,246,0.12);
}
.option-btn:disabled { cursor: default; }
.option-btn.selected-exam {
    border-color: #3b82f6;
    background: #eff6ff;
}
.option-btn.correct  { border-color: #22c55e; background: #f0fdf4; color: #166534; }
.option-btn.incorrect { border-color: #ef4444; background: #fef2f2; color: #991b1b; }

.option-letter {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 28px; height: 28px;
    min-width: 28px;
    margin-right: 12px;
    border-radius: 50%;
    font-size: 0.75rem;
    font-weight: 700;
    background: #f1f5f9;
    color: #475569;
    transition: background 0.15s, color 0.15s;
}
.option-btn.selected-exam .option-letter { background: #3b82f6; color: #fff; }
.option-btn.correct  .option-letter { background: #22c55e; color: #fff; }
.option-btn.incorrect .option-letter { background: #ef4444; color: #fff; }

/* ── Stat / Chart Cards ── */
.stat-card {
    background: #fff;
    border-radius: 16px;
    padding: 24px;
    border: 1px solid #e9eef6;
    box-shadow: 0 1px 3px rgba(0,0,0,0.04), 0 4px 16px rgba(0,0,0,0.04);
    transition: box-shadow 0.2s;
}
.stat-card:hover { box-shadow: 0 4px 24px rgba(0,0,0,0.08); }
.chart-container {
    background: #fff;
    border-radius: 16px;
    border: 1px solid #e9eef6;
    box-shadow: 0 1px 3px rgba(0,0,0,0.04);
    padding: 24px;
}

/* ── Mode selector tabs ── */
.mode-tab {
    flex: 1;
    padding: 10px;
    font-size: 0.85rem;
    font-weight: 600;
    border: 1.5px solid #e2e8f0;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.15s;
    text-align: center;
    background: #fff;
    color: #64748b;
}
.mode-tab.active {
    border-color: #1e40af;
    background: #eff6ff;
    color: #1e40af;
}

/* ── Flag button ── */
.flag-btn {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 5px 12px;
    border-radius: 8px;
    font-size: 0.75rem;
    font-weight: 600;
    border: 1.5px solid #e2e8f0;
    cursor: pointer;
    background: #fff;
    color: #94a3b8;
    transition: all 0.15s;
}
.flag-btn:hover { border-color: #f59e0b; color: #f59e0b; background: #fefce8; }
.flag-btn.flagged { border-color: #f59e0b; color: #d97706; background: #fef3c7; }

/* ── Pause overlay ── */
.quiz-paused-overlay {
    position: absolute;
    inset: 0;
    backdrop-filter: blur(6px);
    background: rgba(255,255,255,0.82);
    border-radius: 16px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 10;
}

/* ── Pause button ── */
.pause-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 14px;
    border-radius: 8px;
    font-size: 0.8rem;
    font-weight: 600;
    border: 1.5px solid #e2e8f0;
    background: #fff;
    color: #64748b;
    cursor: pointer;
    transition: all 0.15s;
}
.pause-btn:hover { border-color: #94a3b8; background: #f8fafc; }
.pause-btn.paused { border-color: #3b82f6; color: #2563eb; background: #eff6ff; }

/* ── Exam Navigator ── */
.nav-panel {
    display: flex;
    flex-direction: column;
    max-height: calc(100vh - 120px);
    overflow: hidden;
}
.nav-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(34px, 1fr));
    gap: 5px;
    overflow-y: auto;
    max-height: 45vh;
    padding-right: 2px;
    scrollbar-width: thin;
    scrollbar-color: #cbd5e1 transparent;
}
.dark .nav-grid { scrollbar-color: #3f3f46 transparent; }
.nav-grid::-webkit-scrollbar { width: 4px; }
.nav-grid::-webkit-scrollbar-thumb { background: #cbd5e1; border-radius: 4px; }
.dark .nav-grid::-webkit-scrollbar-thumb { background: #3f3f46; }
.nav-cell {
    aspect-ratio: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 6px;
    font-size: 0.7rem;
    font-weight: 700;
    cursor: pointer;
    border: 2px solid transparent;
    transition: all 0.12s;
    background: #f1f5f9;
    color: #64748b;
}
.nav-cell:hover   { border-color: #94a3b8; }
.nav-cell.current { border-color: #3b82f6 !important; box-shadow: 0 0 0 2px rgba(59,130,246,0.3); }
.nav-cell.answered  { background: #dbeafe; color: #1e40af; }
.nav-cell.flagged   { background: #fef3c7; color: #d97706; }
.nav-cell.ans-flag  { background: #fde68a; color: #b45309; } /* answered + flagged */
.nav-cell.r-correct { background: #dcfce7; color: #166534; }
.nav-cell.r-incorrect { background: #fee2e2; color: #991b1b; }

/* ── Confidence buttons ── */
.confidence-btn {
    flex: 1;
    padding: 8px 12px;
    border-radius: 10px;
    font-size: 0.8rem;
    font-weight: 600;
    border: 1.5px solid;
    cursor: pointer;
    text-align: center;
    transition: all 0.15s;
}
.confidence-btn.sure    { border-color: #22c55e; color: #16a34a; background: #f0fdf4; }
.confidence-btn.sure:hover    { background: #dcfce7; }
.confidence-btn.unsure  { border-color: #f59e0b; color: #d97706; background: #fefce8; }
.confidence-btn.unsure:hover  { background: #fef3c7; }
.confidence-btn.guessing { border-color: #ef4444; color: #dc2626; background: #fef2f2; }
.confidence-btn.guessing:hover { background: #fee2e2; }

/* ── Progress bar ── */
.progress-bar-track { height: 6px; background: #e2e8f0; border-radius: 999px; overflow: hidden; }
.progress-bar-fill  { height: 100%; background: linear-gradient(90deg,#3b82f6,#8b5cf6); border-radius: 999px; transition: width 0.5s ease; }

/* ── Review grid (post-exam) ── */
.review-cell {
    aspect-ratio: 1;
    display: flex; align-items: center; justify-content: center;
    border-radius: 8px;
    font-size: 0.75rem; font-weight: 700;
    cursor: pointer;
    transition: transform 0.1s;
    border: 2px solid transparent;
}
.review-cell:hover { transform: scale(1.12); }
.review-cell.r-correct   { background: #dcfce7; color: #166534; }
.review-cell.r-incorrect { background: #fee2e2; color: #991b1b; }
.review-cell.r-flagged   { outline: 2px solid #f59e0b; outline-offset: 1px; }
.review-cell.r-selected  { border-color: #1e40af; }

/* ── Tags / Pills ── */
.subject-pill {
    display: inline-block; padding: 3px 10px; border-radius: 999px;
    font-size: 0.68rem; font-weight: 600; letter-spacing: 0.05em; text-transform: uppercase;
}
.kbd {
    display: inline-flex; align-items: center; justify-content: center;
    padding: 1px 6px; border-radius: 4px;
    font-size: 0.65rem; font-weight: 700; font-family: monospace;
    background: #f1f5f9; color: #475569;
    border: 1px solid #cbd5e1;
}

/* ── Form inputs / buttons ── */
.form-input {
    width: 100%; padding: 10px 14px;
    border: 1.5px solid #e2e8f0; border-radius: 10px;
    font-size: 0.9rem; color: #1e293b; background: #fff;
    transition: border-color 0.15s, box-shadow 0.15s; outline: none;
}
.form-input:focus { border-color: #3b82f6; box-shadow: 0 0 0 3px rgba(59,130,246,0.15); }

.btn-primary {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 10px 20px; font-size: 0.875rem; font-weight: 600; color: #fff;
    background: linear-gradient(135deg,#1a2744,#2d4080);
    border-radius: 10px; border: none; cursor: pointer;
    transition: opacity 0.15s, transform 0.1s;
}
.btn-primary:hover { opacity: 0.92; }
.btn-primary:active { transform: scale(0.97); }

.btn-success {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 10px 20px; font-size: 0.875rem; font-weight: 600; color: #fff;
    background: linear-gradient(135deg,#16a34a,#15803d);
    border-radius: 10px; border: none; cursor: pointer;
    transition: opacity 0.15s, transform 0.1s;
}
.btn-success:hover { opacity: 0.9; }

.btn-danger {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 10px 20px; font-size: 0.875rem; font-weight: 600; color: #fff;
    background: linear-gradient(135deg,#dc2626,#b91c1c);
    border-radius: 10px; border: none; cursor: pointer;
    transition: opacity 0.15s;
}
.btn-danger:hover { opacity: 0.9; }

/* ── Misc ── */
.spinner { width: 32px; height: 32px; border: 3px solid #e2e8f0; border-top-color: #3b82f6; border-radius: 50%; animation: spin 0.7s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

.explanation-box { background: #f8faff; border: 1px solid #dbeafe; border-radius: 12px; padding: 16px 20px; margin-top: 12px; }

.reading-row { display: flex; align-items: center; justify-content: space-between; padding: 10px 0; border-bottom: 1px solid #f1f5f9; font-size: 0.875rem; }
.reading-row:last-child { border-bottom: none; }

.empty-state { text-align: center; padding: 60px 20px; color: #94a3b8; }
.empty-state svg { margin: 0 auto 16px; }

/* ── Toast ── */
#toast { position: fixed; bottom: 24px; right: 24px; padding: 12px 20px; border-radius: 12px; font-size: 0.875rem; font-weight: 500; color: #fff; z-index: 9999; opacity: 0; transform: translateY(8px); transition: opacity 0.3s, transform 0.3s; pointer-events: none; }
#toast.show { opacity: 1; transform: translateY(0); }
#toast.success { background: #16a34a; }
#toast.error   { background: #dc2626; }
#toast.info    { background: #2563eb; }

/* ── Scrollbar ── */
main::-webkit-scrollbar { width: 6px; }
main::-webkit-scrollbar-track { background: transparent; }
main::-webkit-scrollbar-thumb { background: #cbd5e1; border-radius: 999px; }
main::-webkit-scrollbar-thumb:hover { background: #94a3b8; }

/* ── Keyboard shortcut hint bar ── */
.shortcut-bar { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; font-size: 0.72rem; color: #94a3b8; }
.shortcut-bar span { display: flex; align-items: center; gap: 3px; }

/* Markdown Table Styles overrides */
.prose table {
    border-collapse: collapse;
    width: 100%;
    margin-top: 1rem;
    margin-bottom: 1rem;
    font-size: 0.875rem;
}
.prose thead {
    background-color: #f8fafc;
    border-bottom: 2px solid #e2e8f0;
}
.prose th, .prose td {
    border: 1px solid #e2e8f0;
    padding: 0.5rem 0.75rem;
    text-align: left;
}
.prose th {
    font-weight: 600;
    color: #334155;
}
.prose tbody tr:nth-child(even) {
    background-color: #f8fafc;
}


/* =========================================
   DARK MODE OVERRIDES (using .dark class)
   ========================================= */

.dark .flag-btn {
    background: #18181b;
    border-color: #27272a;
    color: #a1a1aa;
}
.dark .flag-btn:hover { border-color: #f59e0b; color: #fbbf24; background: #422006; }
.dark .flag-btn.flagged { border-color: #f59e0b; color: #f59e0b; background: #78350f; }

.dark .quiz-paused-overlay { background: rgba(0,0,0,0.85); }

.dark .pause-btn { background: #18181b; border-color: #27272a; color: #a1a1aa; }
.dark .pause-btn:hover { border-color: #3f3f46; background: #27272a; }
.dark .pause-btn.paused { border-color: #3b82f6; color: #60a5fa; background: #1e3a8a; }

.dark .nav-cell { background: #27272a; color: #a1a1aa; }
.dark .nav-cell:hover { border-color: #52525b; }
.dark .nav-cell.current { box-shadow: 0 0 0 2px rgba(96,165,250,0.4); }
.dark .nav-cell.answered { background: #1e3a8a; color: #93c5fd; }
.dark .nav-cell.flagged { background: #78350f; color: #fbbf24; }
.dark .nav-cell.ans-flag { background: #92400e; color: #fde68a; }
.dark .nav-cell.r-correct { background: #14532d; color: #86efac; }
.dark .nav-cell.r-incorrect { background: #7f1d1d; color: #fca5a5; }

.dark .confidence-btn.sure { border-color: #4ade80; color: #4ade80; background: #14532d; }
.dark .confidence-btn.sure:hover { background: #166534; }
.dark .confidence-btn.unsure { border-color: #fbbf24; color: #fbbf24; background: #78350f; }
.dark .confidence-btn.unsure:hover { background: #92400e; }
.dark .confidence-btn.guessing { border-color: #f87171; color: #f87171; background: #7f1d1d; }
.dark .confidence-btn.guessing:hover { background: #991b1b; }

.dark .progress-bar-track { background: #27272a; }

.dark .review-cell.r-correct { background: #14532d; color: #86efac; }
.dark .review-cell.r-incorrect { background: #7f1d1d; color: #fca5a5; }

.dark .kbd { background: #27272a; color: #d4d4d8; border-color: #3f3f46; }

.dark .form-input { background: #18181b; color: #f4f4f5; border-color: #27272a; }
.dark .form-input:focus { box-shadow: 0 0 0 3px rgba(96,165,250,0.25); }

.dark .explanation-box { background: #18181b; border-color: #27272a; }

.dark .reading-row { border-bottom-color: #27272a; }

.dark main::-webkit-scrollbar-thumb { background: #3f3f46; }
.dark main::-webkit-scrollbar-thumb:hover { background: #52525b; }

/* Prose overrides for Dark Mode */
.dark .prose table { border-collapse: collapse; width: 100%; margin-top: 1rem; margin-bottom: 1rem; font-size: 0.875rem; }
.dark .prose thead { background-color: #18181b; border-bottom: 2px solid #27272a; }
.dark .prose th, .dark .prose td { border: 1px solid #27272a; padding: 0.5rem 0.75rem; }
.dark .prose th { font-weight: 600; color: #f4f4f5; }
.dark .prose tbody tr:nth-child(even) { background-color: #18181b; }
.dark .prose p, .dark .prose li, .dark .prose td { color: #d4d4d8; }
.dark .prose strong { color: #f4f4f5; }

/* ── Dark mode: mode tabs ── */
.dark .mode-tab { background: #18181b; border-color: #27272a; color: #a1a1aa; }
.dark .mode-tab.active { background: #1e3a8a; border-color: #3b82f6; color: #bfdbfe; }
.dark .mode-tab:hover:not(.active) { background: #27272a; border-color: #3f3f46; }

/* ── Dark mode: nav legend dots ── */
.dark .nav-legend-unanswered { background: #3f3f46; }
.dark .nav-legend-answered   { background: #1e3a8a; }
.dark .nav-legend-flagged    { background: #78350f; }

/* ── Dark mode: stat cards ── */
.dark .stat-card {
    background: #18181b;
    border-color: #27272a;
    box-shadow: 0 4px 6px -1px rgba(0,0,0,0.3);
}
.dark .chart-container {
    background: #18181b;
    border-color: #27272a;
}

.dark .option-btn {
    background: #18181b;
    color: #f4f4f5;
    border-color: #27272a;
}
.dark .option-btn:hover { background: #27272a; border-color: #3f3f46; }
.dark .option-btn.selected { background: #1e3a8a; border-color: #3b82f6; color: #bfdbfe; }
.dark .option-btn.selected-exam { background: #1e3a8a; border-color: #3b82f6; color: #bfdbfe; }
.dark .option-btn.correct { background: #14532d; border-color: #22c55e; color: #86efac; }
.dark .option-btn.incorrect { background: #7f1d1d; border-color: #ef4444; color: #fca5a5; }

.dark .option-letter { background: #3f3f46; color: #d4d4d8; }
.dark .option-btn:hover .option-letter { background: #52525b; }
.dark .option-btn.selected .option-letter { background: #2563eb; color: #fff; }
.dark .option-btn.selected-exam .option-letter { background: #2563eb; color: #fff; }
.dark .option-btn.correct .option-letter { background: #16a34a; color: #fff; }
.dark .option-btn.incorrect .option-letter { background: #dc2626; color: #fff; }