/**
 * DTM Quiz System - Main Stylesheet
 * Version: 1.1
 * 
 * v1.1 Changes:
 * - Selection screen styles
 * - Mobile-friendly compact layout
 * - Chip/tag selection UI
 */

/* ==========================================================================
   CSS Variables & Theme
   ========================================================================== */
:root {
    /* Primary Colors - DAW Inspired */
    --quiz-bg-primary: #0d0d12;
    --quiz-bg-secondary: #151520;
    --quiz-bg-card: #1a1a28;
    --quiz-bg-hover: #222235;
    
    /* Accent Colors - Neon */
    --quiz-accent-primary: #6366f1;
    --quiz-accent-secondary: #8b5cf6;
    --quiz-accent-cyan: #22d3ee;
    --quiz-accent-pink: #ec4899;
    
    /* Feedback Colors */
    --quiz-correct: #10b981;
    --quiz-correct-glow: rgba(16, 185, 129, 0.3);
    --quiz-incorrect: #ef4444;
    --quiz-incorrect-glow: rgba(239, 68, 68, 0.3);
    --quiz-hint: #f59e0b;
    
    /* Text Colors */
    --quiz-text-primary: #f8fafc;
    --quiz-text-secondary: #94a3b8;
    --quiz-text-muted: #64748b;
    
    /* Borders & Shadows */
    --quiz-border: rgba(255, 255, 255, 0.08);
    --quiz-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    
    /* Typography */
    --quiz-font-display: 'M PLUS Rounded 1c', 'Hiragino Sans', 'Yu Gothic', sans-serif;
    --quiz-font-body: 'M PLUS Rounded 1c', 'Hiragino Sans', 'Yu Gothic', sans-serif;
    --quiz-font-mono: 'JetBrains Mono', 'Fira Code', monospace;
    
    /* Spacing */
    --quiz-radius-sm: 8px;
    --quiz-radius-md: 12px;
    --quiz-radius-lg: 16px;
    --quiz-radius-xl: 20px;
    
    /* Transitions */
    --quiz-transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --quiz-transition-normal: 300ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ==========================================================================
   Base & Container
   ========================================================================== */
.quiz-container {
    font-family: var(--quiz-font-body);
    background: var(--quiz-bg-primary);
    min-height: 100vh;
    color: var(--quiz-text-primary);
    position: relative;
    overflow-x: hidden;
}

.quiz-container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        radial-gradient(ellipse at 20% 20%, rgba(99, 102, 241, 0.08) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 80%, rgba(139, 92, 246, 0.06) 0%, transparent 50%);
    pointer-events: none;
    z-index: 0;
}

.quiz-wrapper {
    position: relative;
    z-index: 1;
    max-width: 700px;
    margin: 0 auto;
    padding: 24px 16px;
}

/* ==========================================================================
   Selection Screen (NEW)
   ========================================================================== */
.quiz-selection-card {
    padding: 24px 20px !important;
}

.quiz-selection {
    text-align: center;
}

.quiz-selection-header {
    margin-bottom: 24px;
}

.quiz-selection-icon {
    font-size: 3rem;
    margin-bottom: 12px;
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-8px); }
}

.quiz-selection-title {
    font-size: 1.6rem;
    font-weight: 700;
    margin: 0 0 8px 0;
    color: var(--quiz-text-primary);
}

.quiz-selection-subtitle {
    font-size: 0.9rem;
    color: var(--quiz-text-secondary);
    margin: 0;
}

/* Filter Sections */
.quiz-filter-section {
    margin-bottom: 20px;
    text-align: left;
}

.quiz-filter-title {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--quiz-text-primary);
    margin: 0 0 10px 0;
}

.quiz-filter-icon {
    font-size: 1rem;
}

.quiz-filter-hint {
    font-size: 0.75rem;
    font-weight: 400;
    color: var(--quiz-text-muted);
    margin-left: auto;
}

/* Chips */
.quiz-filter-chips {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.quiz-chip {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 8px 14px;
    background: var(--quiz-bg-secondary);
    border: 1px solid var(--quiz-border);
    border-radius: 20px;
    font-family: var(--quiz-font-body);
    font-size: 0.85rem;
    color: var(--quiz-text-secondary);
    cursor: pointer;
    transition: all var(--quiz-transition-fast);
}

.quiz-chip:hover {
    border-color: var(--quiz-accent-primary);
    color: var(--quiz-text-primary);
}

.quiz-chip.selected {
    background: var(--quiz-accent-primary);
    border-color: var(--quiz-accent-primary);
    color: white;
}

.quiz-chip-difficulty.selected {
    background: var(--chip-color, var(--quiz-accent-primary));
    border-color: var(--chip-color, var(--quiz-accent-primary));
}

.quiz-chip-difficulty[data-slug="beginner"].selected { background: #10b981; border-color: #10b981; }
.quiz-chip-difficulty[data-slug="intermediate"].selected { background: #3b82f6; border-color: #3b82f6; }
.quiz-chip-difficulty[data-slug="advanced"].selected { background: #f59e0b; border-color: #f59e0b; }
.quiz-chip-difficulty[data-slug="expert"].selected { background: #ef4444; border-color: #ef4444; }

.quiz-chip-icon {
    font-size: 1rem;
}

.quiz-chip-label {
    white-space: nowrap;
}

/* Limit Selector */
.quiz-limit-section {
    text-align: center;
}

.quiz-limit-selector {
    display: flex;
    justify-content: center;
    gap: 8px;
    flex-wrap: wrap;
}

.quiz-limit-btn {
    padding: 8px 16px;
    background: var(--quiz-bg-secondary);
    border: 1px solid var(--quiz-border);
    border-radius: var(--quiz-radius-md);
    font-family: var(--quiz-font-body);
    font-size: 0.85rem;
    color: var(--quiz-text-secondary);
    cursor: pointer;
    transition: all var(--quiz-transition-fast);
}

.quiz-limit-btn:hover {
    border-color: var(--quiz-accent-primary);
}

.quiz-limit-btn.active {
    background: var(--quiz-accent-primary);
    border-color: var(--quiz-accent-primary);
    color: white;
}

/* Selection Info */
.quiz-selection-info {
    display: flex;
    justify-content: center;
    gap: 16px;
    margin: 20px 0;
    flex-wrap: wrap;
}

.quiz-selection-info-item {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.9rem;
    color: var(--quiz-text-secondary);
}

.quiz-selection-info-item strong {
    color: var(--quiz-accent-cyan);
    font-family: var(--quiz-font-mono);
}

.info-sub {
    font-size: 0.8rem;
    color: var(--quiz-text-muted);
}

/* Start Button */
.quiz-start-btn {
    width: 100%;
    max-width: 300px;
    margin: 0 auto;
    display: block;
}

/* ==========================================================================
   Header & Progress
   ========================================================================== */
.quiz-header {
    margin-bottom: 16px;
}

.quiz-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
    flex-wrap: wrap;
    gap: 8px;
}

.quiz-category-badge {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 4px 10px;
    background: linear-gradient(135deg, var(--quiz-accent-primary), var(--quiz-accent-secondary));
    border-radius: 16px;
    font-size: 0.75rem;
    font-weight: 600;
}

.quiz-difficulty-badge {
    padding: 4px 10px;
    background: var(--quiz-bg-card);
    border: 1px solid var(--quiz-border);
    border-radius: 16px;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--quiz-text-secondary);
}

.quiz-difficulty-badge.beginner { border-color: #10b981; color: #10b981; }
.quiz-difficulty-badge.intermediate { border-color: #3b82f6; color: #3b82f6; }
.quiz-difficulty-badge.advanced { border-color: #f59e0b; color: #f59e0b; }
.quiz-difficulty-badge.expert { border-color: #ef4444; color: #ef4444; }

/* Progress Bar */
.quiz-progress-container {
    background: var(--quiz-bg-secondary);
    border-radius: var(--quiz-radius-md);
    padding: 12px 16px;
    border: 1px solid var(--quiz-border);
}

.quiz-progress-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 8px;
    font-size: 0.8rem;
}

.quiz-progress-question {
    color: var(--quiz-text-primary);
    font-weight: 600;
}

.quiz-progress-question span {
    color: var(--quiz-accent-cyan);
    font-family: var(--quiz-font-mono);
}

.quiz-progress-score {
    color: var(--quiz-text-secondary);
}

.quiz-progress-score span {
    color: var(--quiz-correct);
    font-weight: 600;
    font-family: var(--quiz-font-mono);
}

.quiz-progress-bar {
    height: 4px;
    background: var(--quiz-bg-primary);
    border-radius: 2px;
    overflow: hidden;
}

.quiz-progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--quiz-accent-primary), var(--quiz-accent-cyan));
    border-radius: 2px;
    transition: width var(--quiz-transition-normal);
}

/* ==========================================================================
   Timer
   ========================================================================== */
.quiz-timer {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 8px 16px;
    background: var(--quiz-bg-card);
    border-radius: var(--quiz-radius-md);
    border: 1px solid var(--quiz-border);
    margin-bottom: 16px;
}

.quiz-timer-icon {
    width: 18px;
    height: 18px;
    color: var(--quiz-accent-cyan);
}

.quiz-timer-value {
    font-family: var(--quiz-font-mono);
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--quiz-text-primary);
    min-width: 30px;
    text-align: center;
}

.quiz-timer-unit {
    color: var(--quiz-text-muted);
    font-size: 0.8rem;
}

.quiz-timer.warning .quiz-timer-value {
    color: var(--quiz-hint);
    animation: pulse 0.5s ease-in-out infinite;
}

.quiz-timer.critical .quiz-timer-value {
    color: var(--quiz-incorrect);
    animation: pulse 0.3s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

/* ==========================================================================
   Question Card
   ========================================================================== */
.quiz-question-card {
    background: var(--quiz-bg-card);
    border-radius: var(--quiz-radius-xl);
    border: 1px solid var(--quiz-border);
    padding: 20px;
    margin-bottom: 16px;
    box-shadow: var(--quiz-shadow);
    position: relative;
    overflow: hidden;
}

.quiz-question-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--quiz-accent-primary), var(--quiz-accent-secondary), var(--quiz-accent-cyan));
}

.quiz-question-header {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 16px;
    flex-wrap: wrap;
}

.quiz-question-number {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    background: linear-gradient(135deg, var(--quiz-accent-primary), var(--quiz-accent-secondary));
    border-radius: 50%;
    font-size: 0.8rem;
    font-weight: 700;
}

.quiz-question-type {
    padding: 3px 8px;
    background: var(--quiz-bg-secondary);
    border-radius: 4px;
    font-size: 0.7rem;
    color: var(--quiz-text-muted);
}

.quiz-question-points-badge {
    margin-left: auto;
    padding: 3px 8px;
    background: rgba(34, 211, 238, 0.1);
    border: 1px solid var(--quiz-accent-cyan);
    border-radius: 4px;
    font-size: 0.7rem;
    color: var(--quiz-accent-cyan);
    font-weight: 600;
}

.quiz-question-text {
    font-size: 1.05rem;
    font-weight: 500;
    line-height: 1.7;
    color: var(--quiz-text-primary);
    margin: 0;
}

.quiz-question-note {
    font-size: 0.8rem;
    color: var(--quiz-hint);
    margin: 12px 0 0 0;
}

.quiz-question-image {
    margin: 16px 0;
    border-radius: var(--quiz-radius-md);
    overflow: hidden;
    border: 1px solid var(--quiz-border);
}

.quiz-question-image img {
    width: 100%;
    height: auto;
    display: block;
}

/* ==========================================================================
   Answer Choices
   ========================================================================== */
.quiz-choices {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-bottom: 16px;
}

.quiz-choice {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px 16px;
    background: var(--quiz-bg-secondary);
    border: 2px solid var(--quiz-border);
    border-radius: var(--quiz-radius-lg);
    cursor: pointer;
    transition: all var(--quiz-transition-fast);
}

.quiz-choice:hover {
    border-color: var(--quiz-accent-primary);
    background: var(--quiz-bg-hover);
}

.quiz-choice-marker {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    background: var(--quiz-bg-card);
    border: 2px solid var(--quiz-border);
    border-radius: 50%;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--quiz-text-secondary);
    flex-shrink: 0;
    transition: all var(--quiz-transition-fast);
}

.quiz-choice:hover .quiz-choice-marker {
    border-color: var(--quiz-accent-primary);
    color: var(--quiz-accent-primary);
}

.quiz-choice-text {
    flex: 1;
    font-size: 0.95rem;
    line-height: 1.5;
    color: var(--quiz-text-primary);
}

/* Selected */
.quiz-choice.selected {
    border-color: var(--quiz-accent-primary);
    background: rgba(99, 102, 241, 0.1);
}

.quiz-choice.selected .quiz-choice-marker {
    background: var(--quiz-accent-primary);
    border-color: var(--quiz-accent-primary);
    color: white;
}

/* Multiple */
.quiz-choice.multiple .quiz-choice-marker {
    border-radius: 6px;
}

/* True/False */
.quiz-choice.truefalse .quiz-choice-marker {
    width: 36px;
    height: 36px;
    font-size: 1.2rem;
}

/* Correct */
.quiz-choice.correct {
    border-color: var(--quiz-correct);
    background: var(--quiz-correct-glow);
}

.quiz-choice.correct .quiz-choice-marker {
    background: var(--quiz-correct);
    border-color: var(--quiz-correct);
    color: white;
}

/* Incorrect */
.quiz-choice.incorrect {
    border-color: var(--quiz-incorrect);
    background: var(--quiz-incorrect-glow);
}

.quiz-choice.incorrect .quiz-choice-marker {
    background: var(--quiz-incorrect);
    border-color: var(--quiz-incorrect);
    color: white;
}

/* Disabled */
.quiz-choice.disabled {
    pointer-events: none;
    opacity: 0.6;
}

.quiz-choice.disabled:not(.correct):not(.incorrect) {
    opacity: 0.4;
}

/* ==========================================================================
   Hint Section
   ========================================================================== */
.quiz-hint-section {
    margin-bottom: 16px;
}

.quiz-hint-button {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    width: 100%;
    padding: 10px 16px;
    background: transparent;
    border: 1px dashed var(--quiz-hint);
    border-radius: var(--quiz-radius-md);
    color: var(--quiz-hint);
    font-family: var(--quiz-font-body);
    font-size: 0.85rem;
    cursor: pointer;
    transition: all var(--quiz-transition-fast);
}

.quiz-hint-button:hover {
    background: rgba(245, 158, 11, 0.1);
    border-style: solid;
}

.quiz-hint-penalty {
    font-size: 0.75rem;
    color: var(--quiz-text-muted);
}

.quiz-hint-content {
    margin-top: 10px;
    padding: 12px 16px;
    background: rgba(245, 158, 11, 0.1);
    border: 1px solid var(--quiz-hint);
    border-radius: var(--quiz-radius-md);
    color: var(--quiz-text-primary);
    font-size: 0.9rem;
    line-height: 1.6;
}

.quiz-hint-content::before {
    content: '💡 ';
}

/* ==========================================================================
   Feedback
   ========================================================================== */
.quiz-feedback {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 12px 16px;
    border-radius: var(--quiz-radius-md);
    margin-bottom: 12px;
    animation: fadeSlideIn 0.3s ease-out;
}

@keyframes fadeSlideIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.quiz-feedback-icon {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    font-size: 1rem;
    flex-shrink: 0;
}

.quiz-feedback.correct {
    background: var(--quiz-correct-glow);
    border: 1px solid var(--quiz-correct);
}

.quiz-feedback.correct .quiz-feedback-icon {
    background: var(--quiz-correct);
    color: white;
}

.quiz-feedback.incorrect {
    background: var(--quiz-incorrect-glow);
    border: 1px solid var(--quiz-incorrect);
}

.quiz-feedback.incorrect .quiz-feedback-icon {
    background: var(--quiz-incorrect);
    color: white;
}

.quiz-feedback-title {
    font-weight: 600;
    font-size: 0.95rem;
}

.quiz-feedback.correct .quiz-feedback-title { color: var(--quiz-correct); }
.quiz-feedback.incorrect .quiz-feedback-title { color: var(--quiz-incorrect); }

.quiz-feedback-points {
    font-size: 0.8rem;
    color: var(--quiz-text-muted);
}

/* ==========================================================================
   Explanation
   ========================================================================== */
.quiz-explanation {
    margin-top: 12px;
    padding: 16px;
    background: var(--quiz-bg-secondary);
    border-radius: var(--quiz-radius-md);
    border-left: 3px solid var(--quiz-accent-cyan);
    animation: fadeSlideIn 0.4s ease-out;
}

.quiz-explanation-title {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--quiz-accent-cyan);
    margin-bottom: 8px;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.quiz-explanation-text {
    font-size: 0.9rem;
    line-height: 1.7;
    color: var(--quiz-text-secondary);
}

.quiz-explanation-text p {
    margin: 0 0 8px 0;
}

.quiz-explanation-text p:last-child {
    margin-bottom: 0;
}

.quiz-explanation-link {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    margin-top: 10px;
    color: var(--quiz-accent-primary);
    text-decoration: none;
    font-size: 0.8rem;
}

.quiz-explanation-link:hover {
    color: var(--quiz-accent-cyan);
}

/* ==========================================================================
   Action Buttons
   ========================================================================== */
.quiz-actions {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.quiz-button {
    flex: 1;
    min-width: 120px;
    padding: 12px 20px;
    border: none;
    border-radius: var(--quiz-radius-md);
    font-family: var(--quiz-font-body);
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--quiz-transition-fast);
}

.quiz-button-primary {
    background: linear-gradient(135deg, var(--quiz-accent-primary), var(--quiz-accent-secondary));
    color: white;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
}

.quiz-button-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.4);
}

.quiz-button-primary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

.quiz-button-secondary {
    background: var(--quiz-bg-card);
    color: var(--quiz-text-primary);
    border: 1px solid var(--quiz-border);
}

.quiz-button-secondary:hover {
    background: var(--quiz-bg-hover);
    border-color: var(--quiz-accent-primary);
}

/* ==========================================================================
   Result Screen
   ========================================================================== */
.quiz-result-card {
    padding: 24px 20px !important;
}

.quiz-result {
    text-align: center;
}

.quiz-result-icon {
    width: 70px;
    height: 70px;
    margin: 0 auto 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    font-size: 2rem;
}

.quiz-result.rank-s .quiz-result-icon { background: linear-gradient(135deg, #fbbf24, #f59e0b); }
.quiz-result.rank-a .quiz-result-icon { background: linear-gradient(135deg, #6366f1, #8b5cf6); }
.quiz-result.rank-b .quiz-result-icon { background: linear-gradient(135deg, #3b82f6, #06b6d4); }
.quiz-result.rank-c .quiz-result-icon { background: linear-gradient(135deg, #10b981, #34d399); }
.quiz-result.rank-d .quiz-result-icon { background: linear-gradient(135deg, #64748b, #94a3b8); }

.quiz-result-score-circle {
    width: 120px;
    height: 120px;
    margin: 0 auto 16px;
    position: relative;
}

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

.quiz-result-score-circle .circle-bg {
    fill: none;
    stroke: var(--quiz-bg-secondary);
    stroke-width: 8;
}

.quiz-result-score-circle .circle-progress {
    fill: none;
    stroke: url(#scoreGradient);
    stroke-width: 8;
    stroke-linecap: round;
    stroke-dasharray: 440;
    stroke-dashoffset: 440;
    animation: circleProgress 1.5s ease-out forwards;
}

@keyframes circleProgress {
    to { stroke-dashoffset: var(--progress-offset, 0); }
}

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

.quiz-result-score-value {
    font-size: 1.8rem;
    font-weight: 700;
    font-family: var(--quiz-font-mono);
    color: var(--quiz-text-primary);
}

.quiz-result-score-label {
    font-size: 0.7rem;
    color: var(--quiz-text-muted);
}

.quiz-result-rank {
    font-size: 2rem;
    font-weight: 800;
    margin-bottom: 4px;
    background: linear-gradient(135deg, var(--quiz-text-primary), var(--quiz-accent-cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.quiz-result-title {
    font-size: 1.2rem;
    font-weight: 600;
    margin: 0 0 4px 0;
    color: var(--quiz-text-primary);
}

.quiz-result-message {
    font-size: 0.85rem;
    color: var(--quiz-text-secondary);
    margin: 0 0 20px 0;
}

.quiz-result-stats {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 20px;
}

.quiz-result-stat {
    text-align: center;
}

.quiz-result-stat-value {
    font-size: 1.5rem;
    font-weight: 700;
    font-family: var(--quiz-font-mono);
    color: var(--quiz-accent-cyan);
    line-height: 1;
}

.quiz-result-stat-label {
    font-size: 0.7rem;
    color: var(--quiz-text-muted);
    margin-top: 2px;
}

.quiz-result-actions {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

/* ==========================================================================
   Review Screen
   ========================================================================== */
.quiz-review-title {
    color: var(--quiz-text-primary);
    font-size: 1.2rem;
    margin: 0 0 16px 0;
}

.quiz-review-card {
    margin-bottom: 12px;
}

.quiz-review-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 12px;
}

.quiz-review-badge {
    padding: 4px 10px;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 600;
}

.quiz-review-badge.correct {
    background: var(--quiz-correct-glow);
    color: var(--quiz-correct);
    border: 1px solid var(--quiz-correct);
}

.quiz-review-badge.incorrect {
    background: var(--quiz-incorrect-glow);
    color: var(--quiz-incorrect);
    border: 1px solid var(--quiz-incorrect);
}

.quiz-review-choices {
    margin-top: 12px;
}

.quiz-review-choices .quiz-choice {
    padding: 10px 12px;
    margin-bottom: 6px;
}

.quiz-review-actions {
    margin-top: 20px;
    justify-content: center;
}

/* ==========================================================================
   Floating Action Button (Mobile)
   ========================================================================== */
.quiz-fab-container {
    display: none;
}

.quiz-fab {
    width: 100%;
    padding: 12px 20px;
}

/* ==========================================================================
   Bottom Sheet (Mobile)
   ========================================================================== */
.quiz-bottom-sheet {
    display: none;
}

/* ==========================================================================
   Desktop: Hide mobile-specific elements
   ========================================================================== */
@media (min-width: 641px) {
    .quiz-fab-container,
    .quiz-bottom-sheet {
        display: none !important;
    }
    
    .quiz-actions-desktop {
        display: flex;
    }
}

/* ==========================================================================
   Loading
   ========================================================================== */
.quiz-loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 200px;
    gap: 16px;
}

.quiz-loading-spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--quiz-bg-secondary);
    border-top-color: var(--quiz-accent-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

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

/* ==========================================================================
   Confetti
   ========================================================================== */
.confetti {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    pointer-events: none;
    z-index: 1000;
}

/* ==========================================================================
   Responsive - Mobile (COMPACT with Bottom Sheet)
   ========================================================================== */
@media (max-width: 640px) {
    .quiz-wrapper {
        padding: 8px;
        padding-bottom: 80px; /* Space for FAB */
    }
    
    /* === Hide desktop actions, show FAB === */
    .quiz-actions-desktop {
        display: none !important;
    }
    
    .quiz-fab-container {
        display: block;
        position: fixed;
        bottom: 70px; /* Above Swell footer */
        left: 12px;
        right: 12px;
        z-index: 100;
        /* 透明背景 */
        background: transparent;
    }
    
    .quiz-fab {
        width: 100%;
        padding: 14px 20px;
        font-size: 1rem;
        border-radius: 12px;
        box-shadow: 0 4px 20px rgba(99, 102, 241, 0.4);
    }
    
    .quiz-fab:disabled {
        opacity: 0.5;
        box-shadow: none;
    }
    
    /* === Bottom Sheet === */
    .quiz-bottom-sheet {
        display: block;
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        z-index: 1000;
        visibility: hidden;
        opacity: 0;
        transition: visibility 0s 0.3s, opacity 0.3s;
    }
    
    .quiz-bottom-sheet.open {
        visibility: visible;
        opacity: 1;
        transition: visibility 0s, opacity 0.3s;
    }
    
    .quiz-bottom-sheet-overlay {
        position: absolute;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        background: rgba(0, 0, 0, 0.6);
    }
    
    .quiz-bottom-sheet-content {
        position: absolute;
        bottom: 70px; /* Above Swell footer */
        left: 10px;
        right: 10px;
        max-height: 55vh;
        background: var(--quiz-bg-card);
        border-radius: 16px;
        padding: 12px 16px 18px;
        transform: translateY(100%);
        transition: transform 0.3s ease-out;
        overflow-y: auto;
        box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.3);
    }
    
    .quiz-bottom-sheet.open .quiz-bottom-sheet-content {
        transform: translateY(0);
    }
    
    .quiz-bottom-sheet-handle {
        width: 40px;
        height: 4px;
        background: var(--quiz-text-muted);
        border-radius: 2px;
        margin: 0 auto 10px;
    }
    
    .quiz-bottom-sheet-header {
        display: flex;
        align-items: center;
        gap: 8px;
        font-size: 1rem;
        font-weight: 600;
        color: var(--quiz-accent-cyan);
        margin-bottom: 10px;
        padding-bottom: 10px;
        border-bottom: 1px solid var(--quiz-border);
    }
    
    .quiz-bottom-sheet-close {
        margin-left: auto;
        background: none;
        border: none;
        color: var(--quiz-text-muted);
        font-size: 1.3rem;
        cursor: pointer;
        padding: 4px 8px;
    }
    
    .quiz-bottom-sheet-body {
        font-size: 0.92rem;
        line-height: 1.6;
        color: var(--quiz-text-secondary);
    }
    
    .quiz-bottom-sheet-actions {
        margin-top: 14px;
        padding-top: 14px;
        border-top: 1px solid var(--quiz-border);
    }
    
    .quiz-bottom-sheet-actions .quiz-button {
        width: 100%;
        padding: 14px 20px;
        font-size: 1rem;
    }
    
    /* Feedback sheet specific */
    .quiz-bottom-sheet-feedback {
        max-height: 50vh;
    }
    
    .quiz-bottom-sheet-feedback .quiz-feedback {
        margin-bottom: 12px;
    }
    
    .quiz-bottom-sheet-feedback .quiz-explanation {
        margin-top: 0;
        padding: 12px 14px;
    }
    
    .quiz-bottom-sheet-feedback .quiz-explanation-title {
        font-size: 0.82rem;
    }
    
    .quiz-bottom-sheet-feedback .quiz-explanation-text {
        font-size: 0.88rem;
    }
    
    /* === Hide inline feedback/explanation on mobile === */
    .quiz-feedback-area,
    .quiz-explanation-area {
        display: none;
    }
    
    /* === Selection Screen === */
    .quiz-selection-card {
        padding: 16px !important;
    }
    
    .quiz-selection-header {
        margin-bottom: 14px;
    }
    
    .quiz-selection-icon {
        font-size: 2.2rem;
        margin-bottom: 6px;
        animation: none;
    }
    
    .quiz-selection-title {
        font-size: 1.25rem;
        margin-bottom: 4px;
    }
    
    .quiz-selection-subtitle {
        font-size: 0.82rem;
    }
    
    .quiz-filter-section {
        margin-bottom: 12px;
    }
    
    .quiz-filter-title {
        font-size: 0.88rem;
        margin-bottom: 8px;
    }
    
    .quiz-filter-hint {
        font-size: 0.7rem;
    }
    
    .quiz-filter-chips {
        gap: 6px;
    }
    
    .quiz-chip {
        padding: 6px 12px;
        font-size: 0.8rem;
        border-radius: 12px;
        gap: 4px;
    }
    
    .quiz-chip-icon {
        font-size: 0.88rem;
    }
    
    .quiz-limit-selector {
        gap: 6px;
    }
    
    .quiz-limit-btn {
        padding: 6px 14px;
        font-size: 0.8rem;
        border-radius: 8px;
    }
    
    .quiz-selection-info {
        margin: 12px 0;
    }
    
    .quiz-selection-info-item {
        font-size: 0.85rem;
    }
    
    .quiz-start-btn {
        padding: 12px 20px;
        font-size: 0.95rem;
    }
    
    /* === Header & Meta === */
    .quiz-header {
        margin-bottom: 8px;
    }
    
    .quiz-meta {
        gap: 6px;
        margin-bottom: 6px;
    }
    
    .quiz-category-badge,
    .quiz-difficulty-badge {
        padding: 3px 10px;
        font-size: 0.72rem;
        border-radius: 10px;
    }
    
    /* === Progress === */
    .quiz-progress-container {
        padding: 8px 12px;
        border-radius: 10px;
    }
    
    .quiz-progress-info {
        font-size: 0.8rem;
        margin-bottom: 5px;
    }
    
    .quiz-progress-bar {
        height: 4px;
    }
    
    /* === Timer === */
    .quiz-timer {
        padding: 5px 12px;
        margin-bottom: 8px;
        border-radius: 10px;
        gap: 5px;
    }
    
    .quiz-timer-icon {
        width: 16px;
        height: 16px;
    }
    
    .quiz-timer-value {
        font-size: 1rem;
        min-width: 26px;
    }
    
    .quiz-timer-unit {
        font-size: 0.72rem;
    }
    
    /* === Question Card === */
    .quiz-question-card {
        padding: 12px 14px;
        border-radius: 12px;
        margin-bottom: 8px;
    }
    
    .quiz-question-card::before {
        height: 3px;
    }
    
    .quiz-question-header {
        margin-bottom: 8px;
        gap: 6px;
    }
    
    .quiz-question-number {
        width: 24px;
        height: 24px;
        font-size: 0.75rem;
    }
    
    .quiz-question-type {
        padding: 3px 8px;
        font-size: 0.68rem;
    }
    
    .quiz-question-points-badge {
        padding: 3px 8px;
        font-size: 0.68rem;
    }
    
    .quiz-question-text {
        font-size: 0.98rem;
        line-height: 1.5;
    }
    
    .quiz-question-note {
        font-size: 0.78rem;
        margin-top: 6px;
    }
    
    /* === Choices === */
    .quiz-choices {
        gap: 6px;
        margin-bottom: 8px;
    }
    
    .quiz-choice {
        padding: 12px 14px;
        gap: 12px;
        border-radius: 10px;
        border-width: 2px;
    }
    
    .quiz-choice-marker {
        width: 26px;
        height: 26px;
        font-size: 0.78rem;
        border-width: 2px;
    }
    
    .quiz-choice-text {
        font-size: 0.92rem;
        line-height: 1.45;
    }
    
    .quiz-choice.truefalse .quiz-choice-marker {
        width: 30px;
        height: 30px;
        font-size: 1.05rem;
    }
    
    /* === Hint Button === */
    .quiz-hint-section {
        margin-bottom: 8px;
    }
    
    .quiz-hint-button {
        padding: 8px 12px;
        font-size: 0.8rem;
        gap: 5px;
        border-radius: 10px;
    }
    
    .quiz-hint-penalty {
        font-size: 0.68rem;
    }
    
    .quiz-hint-content {
        display: none !important; /* Always use sheet on mobile */
    }
    
    /* === Feedback (for sheet) === */
    .quiz-feedback {
        padding: 10px 14px;
        gap: 12px;
        margin-bottom: 10px;
        border-radius: 10px;
    }
    
    .quiz-feedback-icon {
        width: 30px;
        height: 30px;
        font-size: 0.95rem;
    }
    
    .quiz-feedback-title {
        font-size: 0.98rem;
    }
    
    .quiz-feedback-points {
        font-size: 0.82rem;
    }
    
    /* === Explanation (for sheet) === */
    .quiz-explanation {
        margin-top: 10px;
        padding: 12px 14px;
        border-left-width: 3px;
        border-radius: 10px;
    }
    
    .quiz-explanation-title {
        font-size: 0.8rem;
        margin-bottom: 5px;
        gap: 5px;
    }
    
    .quiz-explanation-text {
        font-size: 0.88rem;
        line-height: 1.55;
    }
    
    .quiz-explanation-text p {
        margin: 0 0 6px 0;
    }
    
    .quiz-explanation-link {
        margin-top: 8px;
        font-size: 0.8rem;
    }
    
    /* === Action Buttons === */
    .quiz-actions {
        gap: 8px;
    }
    
    .quiz-button {
        padding: 10px 14px;
        font-size: 0.88rem;
        border-radius: 10px;
        min-width: 100px;
    }
    
    /* === Result Screen === */
    .quiz-result-card {
        padding: 16px !important;
    }
    
    .quiz-result-icon {
        width: 50px;
        height: 50px;
        font-size: 1.5rem;
        margin-bottom: 8px;
    }
    
    .quiz-result-score-circle {
        width: 80px;
        height: 80px;
        margin-bottom: 10px;
    }
    
    .quiz-result-score-circle .circle-bg,
    .quiz-result-score-circle .circle-progress {
        stroke-width: 6;
    }
    
    .quiz-result-score-value {
        font-size: 1.2rem;
    }
    
    .quiz-result-score-label {
        font-size: 0.6rem;
    }
    
    .quiz-result-rank {
        font-size: 1.3rem;
        margin-bottom: 2px;
    }
    
    .quiz-result-title {
        font-size: 1rem;
        margin-bottom: 2px;
    }
    
    .quiz-result-message {
        font-size: 0.8rem;
        margin-bottom: 12px;
    }
    
    .quiz-result-stats {
        gap: 16px;
        margin-bottom: 14px;
    }
    
    .quiz-result-stat-value {
        font-size: 1.1rem;
    }
    
    .quiz-result-stat-label {
        font-size: 0.65rem;
    }
    
    .quiz-result-actions {
        gap: 8px;
    }
    
    .quiz-result-actions .quiz-button {
        padding: 10px 12px;
        font-size: 0.82rem;
    }
    
    /* === Review Screen === */
    .quiz-review-title {
        font-size: 1.05rem;
        margin-bottom: 12px;
    }
    
    .quiz-review-card {
        margin-bottom: 10px;
    }
    
    .quiz-review-header {
        margin-bottom: 8px;
    }
    
    .quiz-review-badge {
        padding: 3px 8px;
        font-size: 0.72rem;
    }
    
    .quiz-review-choices {
        margin-top: 8px;
    }
    
    .quiz-review-choices .quiz-choice {
        padding: 8px 10px;
        margin-bottom: 5px;
    }
    
    .quiz-review-choices .quiz-choice-marker {
        width: 20px;
        height: 20px;
        font-size: 0.68rem;
    }
    
    .quiz-review-choices .quiz-choice-text {
        font-size: 0.82rem;
    }
    
    .quiz-review-actions {
        margin-top: 14px;
    }
    
    /* === Loading === */
    .quiz-loading {
        min-height: 140px;
        gap: 12px;
    }
    
    .quiz-loading-spinner {
        width: 32px;
        height: 32px;
    }
    
    .quiz-loading-text {
        font-size: 0.88rem;
    }
}

/* Extra small devices (< 400px) */
@media (max-width: 400px) {
    .quiz-wrapper {
        padding: 2px;
    }
    
    .quiz-selection-card,
    .quiz-question-card,
    .quiz-result-card {
        padding: 6px !important;
    }
    
    .quiz-selection-icon {
        font-size: 1.2rem;
    }
    
    .quiz-selection-title {
        font-size: 0.9rem;
    }
    
    .quiz-chip {
        padding: 2px 5px;
        font-size: 0.55rem;
    }
    
    .quiz-question-text {
        font-size: 0.72rem;
    }
    
    .quiz-choice {
        padding: 5px 6px;
    }
    
    .quiz-choice-marker {
        width: 16px;
        height: 16px;
        font-size: 0.55rem;
    }
    
    .quiz-choice-text {
        font-size: 0.68rem;
    }
    
    .quiz-result-score-circle {
        width: 50px;
        height: 50px;
    }
    
    .quiz-result-score-value {
        font-size: 0.8rem;
    }
    
    .quiz-result-rank {
        font-size: 0.9rem;
    }
    
    .quiz-result-stat-value {
        font-size: 0.8rem;
    }
    
    .quiz-button {
        padding: 5px 8px;
        font-size: 0.65rem;
    }
}