/* ===== CSS Variables / Theming ===== */
:root {
    --bg-primary: #f5f7fa;
    --bg-secondary: #ffffff;
    --bg-tertiary: #eef1f6;
    --text-primary: #1a1a2e;
    --text-secondary: #4a4a6a;
    --text-muted: #8888a0;
    --border: #d8dce6;
    --accent: #2563eb;
    --accent-hover: #1d4ed8;
    --accent-light: #dbeafe;
    --success: #16a34a;
    --success-light: #dcfce7;
    --danger: #dc2626;
    --danger-light: #fee2e2;
    --warning: #d97706;
    --warning-light: #fef3c7;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
    --shadow-lg: 0 8px 30px rgba(0,0,0,0.12);
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --transition: 0.2s ease;
}

[data-theme="dark"] {
    --bg-primary: #0f1117;
    --bg-secondary: #1a1c25;
    --bg-tertiary: #252830;
    --text-primary: #e8e8f0;
    --text-secondary: #a8a8c0;
    --text-muted: #666680;
    --border: #333348;
    --accent: #3b82f6;
    --accent-hover: #60a5fa;
    --accent-light: #1e3a5f;
    --success: #22c55e;
    --success-light: #14331f;
    --danger: #ef4444;
    --danger-light: #3b1515;
    --warning: #f59e0b;
    --warning-light: #3b2e0a;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.3);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.4);
    --shadow-lg: 0 8px 30px rgba(0,0,0,0.5);
}

/* ===== Reset & Base ===== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    transition: background var(--transition), color var(--transition);
}

/* ===== Header ===== */
.header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1.5rem;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.header-title {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--accent);
}

.header-center {
    display: flex;
    align-items: center;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.timer {
    font-size: 1.25rem;
    font-weight: 700;
    font-variant-numeric: tabular-nums;
    color: var(--text-primary);
    background: var(--bg-tertiary);
    padding: 0.35rem 0.9rem;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.timer.warning {
    color: var(--warning);
    background: var(--warning-light);
}

.timer.danger {
    color: var(--danger);
    background: var(--danger-light);
    animation: pulse 1s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.6; }
}

.timer-icon {
    font-size: 1rem;
}

.progress-text {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
}

/* ===== Progress Bar ===== */
.progress-bar-container {
    height: 4px;
    background: var(--bg-tertiary);
    width: 100%;
}

.progress-bar {
    height: 100%;
    background: var(--accent);
    transition: width 0.4s ease;
    border-radius: 0 2px 2px 0;
}

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.55rem 1.25rem;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
    text-decoration: none;
    gap: 0.4rem;
    white-space: nowrap;
}

.btn:active {
    transform: scale(0.97);
}

.btn-primary {
    background: var(--accent);
    color: #fff;
}

.btn-primary:hover {
    background: var(--accent-hover);
}

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    background: var(--border);
}

.btn-danger {
    background: var(--danger);
    color: #fff;
}

.btn-danger:hover {
    background: #b91c1c;
}

.btn-outline {
    background: transparent;
    color: var(--accent);
    border: 2px solid var(--accent);
}

.btn-outline:hover {
    background: var(--accent-light);
}

.btn-text {
    background: none;
    color: var(--accent);
    padding: 0.4rem 0.6rem;
    border: none;
}

.btn-text:hover {
    text-decoration: underline;
}

.btn-icon {
    background: none;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 1.1rem;
    color: var(--text-secondary);
    transition: all var(--transition);
}

.btn-icon:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.btn-large {
    padding: 0.85rem 2.5rem;
    font-size: 1.05rem;
}

.btn-full {
    width: 100%;
}

.btn-option {
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    border: 2px solid transparent;
    padding: 0.5rem 1.1rem;
}

.btn-option:hover {
    border-color: var(--accent);
    color: var(--text-primary);
}

.btn-option.active {
    background: var(--accent-light);
    color: var(--accent);
    border-color: var(--accent);
}

/* ===== Screens ===== */
.screen {
    display: none;
    padding: 2rem 1.5rem;
    max-width: 1200px;
    margin: 0 auto;
}

.screen.active {
    display: block;
}

.hidden {
    display: none !important;
}

/* ===== Welcome Screen ===== */
.welcome-container {
    text-align: center;
    padding-top: 2rem;
}

.welcome-hero h1 {
    font-size: 2.4rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, var(--accent), #7c3aed);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    font-size: 1.15rem;
    color: var(--text-secondary);
    margin-bottom: 2.5rem;
}

.mode-cards {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    max-width: 800px;
    margin: 0 auto 2rem;
}

.mode-card {
    background: var(--bg-secondary);
    border: 2px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 2rem 1.5rem;
    text-align: left;
    cursor: pointer;
    transition: all 0.25s ease;
    position: relative;
    overflow: hidden;
}

.mode-card:hover {
    border-color: var(--accent);
    box-shadow: var(--shadow-lg);
    transform: translateY(-3px);
}

.mode-icon {
    font-size: 2.2rem;
    margin-bottom: 0.75rem;
}

.mode-card h2 {
    font-size: 1.3rem;
    margin-bottom: 0.4rem;
}

.mode-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.mode-details {
    list-style: none;
    padding: 0;
}

.mode-details li {
    font-size: 0.85rem;
    color: var(--text-secondary);
    padding: 0.25rem 0;
    padding-left: 1.2rem;
    position: relative;
}

.mode-details li::before {
    content: "\2713";
    position: absolute;
    left: 0;
    color: var(--success);
    font-weight: 700;
}

.mode-badge {
    display: inline-block;
    margin-top: 1rem;
    padding: 0.3rem 0.8rem;
    background: var(--accent-light);
    color: var(--accent);
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
}

.mode-badge.training {
    background: var(--success-light);
    color: var(--success);
}

.welcome-footer {
    margin-top: 1rem;
}

/* ===== Training Config Screen ===== */
.config-container {
    max-width: 650px;
    margin: 0 auto;
}

.config-container h2 {
    font-size: 1.6rem;
    margin-bottom: 0.25rem;
}

.back-btn {
    margin-bottom: 1.5rem;
}

.config-section {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    margin-bottom: 1.25rem;
}

.config-section h3 {
    font-size: 1rem;
    margin-bottom: 0.75rem;
    color: var(--text-secondary);
}

.domain-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.6rem;
}

.domain-btn {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.7rem 0.9rem;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--bg-primary);
    cursor: pointer;
    transition: all var(--transition);
    text-align: left;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-primary);
}

.domain-btn:hover {
    border-color: var(--accent);
}

.domain-btn.active {
    border-color: var(--accent);
    background: var(--accent-light);
    color: var(--accent);
}

.domain-num {
    width: 26px;
    height: 26px;
    border-radius: 50%;
    background: var(--bg-tertiary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.8rem;
    flex-shrink: 0;
}

.domain-btn.active .domain-num {
    background: var(--accent);
    color: #fff;
}

.option-row {
    display: flex;
    gap: 0.6rem;
    flex-wrap: wrap;
}

.custom-input-group {
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

.input-small {
    width: 80px;
    padding: 0.45rem 0.6rem;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--bg-primary);
    color: var(--text-primary);
    font-size: 0.9rem;
    font-weight: 600;
}

.input-small:focus {
    outline: none;
    border-color: var(--accent);
}

.toggle-row {
    margin-bottom: 0.75rem;
}

.toggle-row:last-child {
    margin-bottom: 0;
}

.toggle-label {
    display: flex;
    align-items: center;
    justify-content: space-between;
    cursor: pointer;
    font-weight: 500;
}

.toggle-input {
    display: none;
}

.toggle-slider {
    width: 44px;
    height: 24px;
    background: var(--border);
    border-radius: 12px;
    position: relative;
    transition: background var(--transition);
    flex-shrink: 0;
}

.toggle-slider::after {
    content: '';
    position: absolute;
    width: 18px;
    height: 18px;
    background: #fff;
    border-radius: 50%;
    top: 3px;
    left: 3px;
    transition: transform var(--transition);
    box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}

.toggle-input:checked + .toggle-slider {
    background: var(--accent);
}

.toggle-input:checked + .toggle-slider::after {
    transform: translateX(20px);
}

#btn-start-training {
    margin-top: 1rem;
    width: 100%;
}

/* ===== Exam Screen ===== */
.exam-container {
    display: grid;
    grid-template-columns: 1fr 260px;
    gap: 1.5rem;
    max-width: 1100px;
    margin: 0 auto;
    align-items: start;
}

.exam-main {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 1.75rem;
}

.question-header {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    margin-bottom: 1.25rem;
    flex-wrap: wrap;
}

.domain-badge {
    padding: 0.25rem 0.7rem;
    background: var(--accent-light);
    color: var(--accent);
    border-radius: 20px;
    font-size: 0.78rem;
    font-weight: 600;
}

.difficulty-badge {
    padding: 0.25rem 0.7rem;
    border-radius: 20px;
    font-size: 0.78rem;
    font-weight: 600;
}

.difficulty-badge.easy {
    background: var(--success-light);
    color: var(--success);
}

.difficulty-badge.medium {
    background: var(--warning-light);
    color: var(--warning);
}

.difficulty-badge.hard {
    background: var(--danger-light);
    color: var(--danger);
}

.mark-btn {
    margin-left: auto;
    font-size: 0.85rem;
}

.mark-btn.marked {
    color: var(--warning);
    font-weight: 700;
}

.question-text {
    font-size: 1.05rem;
    line-height: 1.7;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.answer-choices {
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
    margin-bottom: 1.25rem;
}

.answer-option {
    display: flex;
    align-items: flex-start;
    gap: 0.8rem;
    padding: 0.9rem 1rem;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition);
    background: var(--bg-primary);
}

.answer-option:hover {
    border-color: var(--accent);
    background: var(--accent-light);
}

.answer-option.selected {
    border-color: var(--accent);
    background: var(--accent-light);
}

.answer-option.correct {
    border-color: var(--success);
    background: var(--success-light);
}

.answer-option.incorrect {
    border-color: var(--danger);
    background: var(--danger-light);
}

.answer-option.disabled {
    pointer-events: none;
}

.answer-letter {
    width: 30px;
    height: 30px;
    border-radius: 50%;
    background: var(--bg-tertiary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.85rem;
    flex-shrink: 0;
    transition: all var(--transition);
}

.answer-option.selected .answer-letter {
    background: var(--accent);
    color: #fff;
}

.answer-option.correct .answer-letter {
    background: var(--success);
    color: #fff;
}

.answer-option.incorrect .answer-letter {
    background: var(--danger);
    color: #fff;
}

.answer-text {
    font-size: 0.95rem;
    padding-top: 0.2rem;
    line-height: 1.5;
}

/* Feedback */
.feedback-panel {
    background: var(--bg-tertiary);
    border-radius: var(--radius-sm);
    padding: 1rem 1.25rem;
    margin-bottom: 1.25rem;
    border-left: 4px solid var(--accent);
}

.feedback-panel.correct {
    border-left-color: var(--success);
}

.feedback-panel.incorrect {
    border-left-color: var(--danger);
}

.feedback-result {
    font-weight: 700;
    margin-bottom: 0.4rem;
    font-size: 0.95rem;
}

.feedback-panel.correct .feedback-result {
    color: var(--success);
}

.feedback-panel.incorrect .feedback-result {
    color: var(--danger);
}

.feedback-explanation {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Exam Nav */
.exam-nav {
    display: flex;
    gap: 0.75rem;
    align-items: center;
}

.exam-nav .btn-primary {
    margin-left: auto;
}

/* Sidebar */
.exam-sidebar {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    position: sticky;
    top: 70px;
}

.exam-sidebar h3 {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
}

.question-palette {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 0.35rem;
    margin-bottom: 1rem;
    max-height: 300px;
    overflow-y: auto;
}

.palette-btn {
    width: 100%;
    aspect-ratio: 1;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--bg-primary);
    cursor: pointer;
    font-size: 0.75rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition);
    color: var(--text-secondary);
}

.palette-btn:hover {
    border-color: var(--accent);
}

.palette-btn.current {
    border-color: var(--accent);
    background: var(--accent);
    color: #fff;
}

.palette-btn.answered {
    background: var(--accent-light);
    border-color: var(--accent);
    color: var(--accent);
}

.palette-btn.marked {
    background: var(--warning-light);
    border-color: var(--warning);
    color: var(--warning);
}

.sidebar-legend {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
    margin-bottom: 1rem;
    padding-top: 0.5rem;
    border-top: 1px solid var(--border);
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 0.3rem;
    font-size: 0.72rem;
    color: var(--text-muted);
}

.dot {
    width: 10px;
    height: 10px;
    border-radius: 3px;
    border: 1px solid var(--border);
}

.dot.current {
    background: var(--accent);
    border-color: var(--accent);
}

.dot.answered {
    background: var(--accent-light);
    border-color: var(--accent);
}

.dot.marked {
    background: var(--warning-light);
    border-color: var(--warning);
}

.dot.unanswered {
    background: var(--bg-primary);
}

/* ===== Results Screen ===== */
.results-container {
    max-width: 750px;
    margin: 0 auto;
}

.results-header {
    text-align: center;
    margin-bottom: 2rem;
}

.results-header h2 {
    font-size: 1.6rem;
    margin-bottom: 0.75rem;
}

.result-badge {
    display: inline-block;
    padding: 0.5rem 1.5rem;
    border-radius: 30px;
    font-size: 1.2rem;
    font-weight: 700;
}

.result-badge.pass {
    background: var(--success-light);
    color: var(--success);
}

.result-badge.fail {
    background: var(--danger-light);
    color: var(--danger);
}

.score-overview {
    display: flex;
    align-items: center;
    gap: 2.5rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 2rem;
    margin-bottom: 2rem;
}

.score-circle-container {
    position: relative;
    width: 140px;
    height: 140px;
    flex-shrink: 0;
}

.score-circle {
    width: 100%;
    height: 100%;
    transform: rotate(-90deg);
}

.score-bg {
    fill: none;
    stroke: var(--bg-tertiary);
    stroke-width: 8;
}

.score-ring {
    fill: none;
    stroke: var(--accent);
    stroke-width: 8;
    stroke-linecap: round;
    stroke-dasharray: 339.29;
    stroke-dashoffset: 339.29;
    transition: stroke-dashoffset 1.5s ease;
}

.score-center {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
}

.score-percent {
    display: block;
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--text-primary);
}

.score-fraction {
    display: block;
    font-size: 0.8rem;
    color: var(--text-muted);
}

.score-stats {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.stat-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.stat-label {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.stat-value {
    font-weight: 700;
    font-size: 1rem;
}

.domain-breakdown {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    margin-bottom: 2rem;
}

.domain-breakdown h3 {
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.domain-bars {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.domain-bar-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.domain-bar-label {
    width: 200px;
    font-size: 0.82rem;
    color: var(--text-secondary);
    flex-shrink: 0;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.domain-bar-track {
    flex: 1;
    height: 22px;
    background: var(--bg-tertiary);
    border-radius: 11px;
    overflow: hidden;
    position: relative;
}

.domain-bar-fill {
    height: 100%;
    border-radius: 11px;
    transition: width 1s ease;
    min-width: 2px;
}

.domain-bar-fill.good {
    background: var(--success);
}

.domain-bar-fill.okay {
    background: var(--warning);
}

.domain-bar-fill.poor {
    background: var(--danger);
}

.domain-bar-value {
    font-size: 0.82rem;
    font-weight: 700;
    width: 45px;
    text-align: right;
    flex-shrink: 0;
}

.results-actions {
    display: flex;
    gap: 0.75rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* ===== Review Screen ===== */
.review-container {
    max-width: 800px;
    margin: 0 auto;
}

.review-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.review-header h2 {
    font-size: 1.4rem;
}

.review-filters {
    display: flex;
    gap: 0.4rem;
}

.review-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.review-item {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    border-left: 4px solid var(--border);
}

.review-item.correct {
    border-left-color: var(--success);
}

.review-item.incorrect {
    border-left-color: var(--danger);
}

.review-q-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.6rem;
    flex-wrap: wrap;
}

.review-q-num {
    font-weight: 700;
    font-size: 0.9rem;
}

.review-q-text {
    font-size: 0.95rem;
    line-height: 1.6;
    margin-bottom: 0.8rem;
}

.review-answers {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
    margin-bottom: 0.8rem;
    font-size: 0.88rem;
}

.review-answer {
    padding: 0.4rem 0.6rem;
    border-radius: 4px;
}

.review-answer.user-selected {
    background: var(--danger-light);
    font-weight: 600;
}

.review-answer.correct-answer {
    background: var(--success-light);
    font-weight: 600;
}

.review-answer.user-correct {
    background: var(--success-light);
    font-weight: 600;
}

.review-explanation {
    background: var(--bg-tertiary);
    padding: 0.8rem 1rem;
    border-radius: var(--radius-sm);
    font-size: 0.88rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* ===== Stats Screen ===== */
.stats-container {
    max-width: 750px;
    margin: 0 auto;
}

.stats-container h2 {
    font-size: 1.6rem;
    margin-bottom: 0.25rem;
}

.stats-content {
    margin-top: 1rem;
}

.stats-empty {
    text-align: center;
    padding: 3rem;
    color: var(--text-muted);
    font-size: 1.05rem;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    text-align: center;
}

.stat-card .stat-value {
    font-size: 1.8rem;
    display: block;
    margin-bottom: 0.25rem;
}

.stat-card .stat-label {
    font-size: 0.85rem;
}

.stats-sessions {
    margin-top: 1.5rem;
}

.stats-sessions h3 {
    margin-bottom: 0.75rem;
    font-size: 1.1rem;
}

.session-item {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 0.9rem 1.1rem;
    margin-bottom: 0.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.9rem;
}

.session-info {
    display: flex;
    flex-direction: column;
    gap: 0.15rem;
}

.session-mode {
    font-weight: 600;
}

.session-date {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.session-score {
    font-weight: 700;
    font-size: 1.1rem;
}

.session-score.pass {
    color: var(--success);
}

.session-score.fail {
    color: var(--danger);
}

.weak-domains {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    margin-top: 1.5rem;
}

.weak-domains h3 {
    margin-bottom: 0.75rem;
    font-size: 1.05rem;
}

.weak-domain-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border);
    font-size: 0.9rem;
}

.weak-domain-item:last-child {
    border-bottom: none;
}

.weak-recommend {
    font-size: 0.8rem;
    color: var(--accent);
    cursor: pointer;
    font-weight: 600;
}

.stats-actions {
    margin-top: 2rem;
    text-align: center;
}

/* ===== Modal ===== */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.modal {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: 2rem;
    max-width: 400px;
    width: 90%;
    box-shadow: var(--shadow-lg);
}

.modal h3 {
    margin-bottom: 0.5rem;
}

.modal p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
}

.modal-actions {
    display: flex;
    gap: 0.75rem;
    justify-content: flex-end;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .mode-cards {
        grid-template-columns: 1fr;
    }

    .exam-container {
        grid-template-columns: 1fr;
    }

    .exam-sidebar {
        position: static;
        order: -1;
    }

    .question-palette {
        grid-template-columns: repeat(8, 1fr);
        max-height: 120px;
    }

    .score-overview {
        flex-direction: column;
        text-align: center;
    }

    .stat-item {
        justify-content: center;
        gap: 0.75rem;
    }

    .domain-grid {
        grid-template-columns: 1fr;
    }

    .domain-bar-label {
        width: 120px;
        font-size: 0.75rem;
    }

    .stats-grid {
        grid-template-columns: 1fr 1fr;
    }

    .review-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .welcome-hero h1 {
        font-size: 1.8rem;
    }

    .header-title {
        font-size: 0.9rem;
    }
}

@media (max-width: 480px) {
    .screen {
        padding: 1rem;
    }

    .stats-grid {
        grid-template-columns: 1fr;
    }

    .question-palette {
        grid-template-columns: repeat(6, 1fr);
    }
}