/* ==================== 现代化 UI 重构 ==================== */
/* 设计：暗色主题 + 玻璃拟态 + 渐变色彩 */

/* Google Fonts */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

/* ==================== CSS 变量 ==================== */
:root {
    /* 主色调 - 紫蓝渐变 */
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --primary-color: #667eea;
    --primary-hover: #5a6fd6;
    --accent-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    
    /* 成功/错误/警告 */
    --success-color: #00d9a5;
    --success-gradient: linear-gradient(135deg, #11998e 0%, #38ef7d 100%);
    --success-hover: #00c495;
    --danger-color: #ff6b6b;
    --danger-gradient: linear-gradient(135deg, #ff6b6b 0%, #ee5a24 100%);
    --danger-hover: #ee5252;
    --warning-color: #ffd93d;
    --secondary-color: #6c7a89;
    --secondary-hover: #5a6874;
    
    /* 暗色背景 */
    --bg-dark: #0a0a1a;
    --bg-darker: #050510;
    --bg-card: rgba(255, 255, 255, 0.03);
    --bg-card-hover: rgba(255, 255, 255, 0.06);
    --bg-input: rgba(255, 255, 255, 0.05);
    
    /* 文字 */
    --text-primary: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.7);
    --text-muted: rgba(255, 255, 255, 0.5);
    
    /* 玻璃效果 */
    --glass-border: rgba(255, 255, 255, 0.1);
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
    --glow-primary: 0 0 40px rgba(102, 126, 234, 0.3);
    --glow-success: 0 0 40px rgba(0, 217, 165, 0.3);
    --glow-danger: 0 0 40px rgba(255, 107, 107, 0.3);
    
    /* 圆角 & 过渡 */
    --radius-sm: 8px;
    --radius: 16px;
    --radius-lg: 24px;
    --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    --quiz-width: 1120px;
    --quiz-height: 720px;
}

/* ==================== 基础重置 ==================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-dark);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
}

/* 动态背景 */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        radial-gradient(ellipse 80% 50% at 20% -20%, rgba(102, 126, 234, 0.15) 0%, transparent 50%),
        radial-gradient(ellipse 60% 40% at 80% 100%, rgba(118, 75, 162, 0.1) 0%, transparent 50%),
        radial-gradient(ellipse 40% 30% at 50% 50%, rgba(240, 147, 251, 0.05) 0%, transparent 50%);
    pointer-events: none;
    z-index: -1;
}

/* ==================== 容器 ==================== */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 30px 24px;
    position: relative;
}

/* ==================== 头部样式 ==================== */
header {
    text-align: center;
    margin-bottom: 40px;
    padding: 20px 0;
}

header h1 {
    font-size: 2.2rem;
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 24px;
    letter-spacing: -0.5px;
    text-shadow: 0 0 60px rgba(102, 126, 234, 0.5);
}

.header-right {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
}

nav {
    display: flex;
    justify-content: center;
    gap: 12px;
    flex-wrap: wrap;
}

.nav-btn {
    padding: 12px 28px;
    border: 1px solid var(--glass-border);
    background: var(--bg-card);
    color: var(--text-secondary);
    border-radius: 50px;
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 500;
    font-family: inherit;
    transition: var(--transition);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.nav-btn:hover {
    background: var(--bg-card-hover);
    border-color: var(--primary-color);
    color: var(--text-primary);
    transform: translateY(-2px);
}

.nav-btn.active {
    background: var(--primary-gradient);
    border-color: transparent;
    color: white;
    box-shadow: var(--glow-primary);
}

/* ==================== 卡片样式 ==================== */
.card {
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius);
    padding: 28px;
    margin-bottom: 24px;
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    box-shadow: var(--glass-shadow);
    transition: var(--transition);
}

.card:hover {
    background: var(--bg-card-hover);
    border-color: rgba(255, 255, 255, 0.15);
}

.card h2 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 24px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--glass-border);
    display: flex;
    align-items: center;
    gap: 10px;
}

/* ==================== 表单样式 ==================== */
.form-group {
    margin-bottom: 24px;
}

.form-group label {
    display: block;
    font-weight: 500;
    margin-bottom: 10px;
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 14px 18px;
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    font-family: inherit;
    background: var(--bg-input);
    color: var(--text-primary);
    transition: var(--transition);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--text-muted);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    background: rgba(102, 126, 234, 0.1);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 220px;
    line-height: 1.7;
}

.form-group small {
    display: block;
    margin-top: 8px;
    color: var(--text-muted);
    font-size: 0.85rem;
}

/* ==================== 按钮样式 ==================== */
.btn {
    padding: 14px 32px;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    font-family: inherit;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(255,255,255,0.2) 0%, transparent 50%);
    opacity: 0;
    transition: var(--transition);
}

.btn:hover::before {
    opacity: 1;
}

.btn.primary {
    background: var(--primary-gradient);
    color: white;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.btn.primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.5);
}

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

.btn.secondary:hover {
    background: var(--bg-card-hover);
    border-color: var(--primary-color);
    color: var(--text-primary);
    transform: translateY(-2px);
}

.btn.success {
    background: var(--success-gradient);
    color: white;
    box-shadow: 0 4px 15px rgba(0, 217, 165, 0.4);
}

.btn.success:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0, 217, 165, 0.5);
}

.btn.danger {
    background: var(--danger-gradient);
    color: white;
    box-shadow: 0 4px 15px rgba(255, 107, 107, 0.4);
}

.btn.danger:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(255, 107, 107, 0.5);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
}

.btn:active {
    transform: translateY(0) scale(0.98);
}

/* ==================== 加载动画 ==================== */
.loading-spinner {
    width: 20px;
    height: 20px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

/* ==================== 页面切换动画 ==================== */
.page {
    display: none;
}

.page.active {
    display: block;
    animation: fadeSlideIn 0.4s ease-out;
}

@keyframes fadeSlideIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ==================== 文件上传区域 ==================== */
.upload-area {
    border: 2px dashed var(--glass-border);
    border-radius: var(--radius);
    padding: 40px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    background: var(--bg-input);
    position: relative;
}

.upload-area:hover {
    border-color: var(--primary-color);
    background: rgba(102, 126, 234, 0.1);
}

.upload-area.dragover {
    border-color: var(--primary-color);
    background: rgba(102, 126, 234, 0.15);
    box-shadow: var(--glow-primary);
}

.upload-content {
    pointer-events: none;
}

.upload-icon {
    font-size: 3.5rem;
    display: block;
    margin-bottom: 16px;
    filter: grayscale(0.3);
}

.upload-area p {
    margin: 6px 0;
    color: var(--text-secondary);
}

.upload-hint {
    font-size: 0.85rem;
    color: var(--text-muted) !important;
}

.upload-progress,
.upload-success {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
}

.upload-success {
    color: var(--success-color);
    flex-wrap: wrap;
}

.btn-clear {
    background: transparent;
    border: 1px solid var(--danger-color);
    color: var(--danger-color);
    padding: 6px 14px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.85rem;
    font-family: inherit;
    margin-left: 12px;
    transition: var(--transition);
}

.btn-clear:hover {
    background: var(--danger-color);
    color: white;
}

/* ==================== 乱序选项 ==================== */
.shuffle-options {
    display: flex;
    gap: 24px;
    margin-bottom: 24px;
    padding: 16px 20px;
    background: var(--bg-input);
    border-radius: var(--radius-sm);
    border: 1px solid var(--glass-border);
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
    font-size: 0.95rem;
    color: var(--text-secondary);
    transition: var(--transition);
}

.checkbox-label input[type="checkbox"] {
    width: 20px;
    height: 20px;
    cursor: pointer;
    accent-color: var(--primary-color);
    border-radius: 4px;
}

.checkbox-label:hover {
    color: var(--primary-color);
}

/* ==================== 试卷列表 ==================== */
.exams-list {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.exam-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 24px;
    background: var(--bg-input);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-sm);
    transition: var(--transition);
}

.exam-item:hover {
    background: var(--bg-card-hover);
    border-color: var(--primary-color);
    transform: translateX(4px);
}

.exam-info h3 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 6px;
}

.exam-meta {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.exam-actions {
    display: flex;
    gap: 10px;
}

.exam-actions .btn {
    padding: 10px 18px;
    font-size: 0.9rem;
}

.empty-message {
    text-align: center;
    color: var(--text-muted);
    padding: 50px;
    font-size: 1.1rem;
}

/* ==================== 答题页面布局 ==================== */
.quiz-layout {
    width: min(var(--quiz-width), 100%);
    min-height: var(--quiz-height);
    display: flex;
    flex-direction: row;
    gap: 24px;
    align-items: flex-start;
    margin: 0 auto;
}

.quiz-main {
    flex: 1;
    min-width: 0;
}

/* ==================== 答题卡侧边栏 ==================== */
.answer-sheet-sidebar {
    width: 280px;
    flex-shrink: 0;
    position: sticky;
    top: 24px;
}

.answer-sheet-card {
    padding: 20px;
}

.answer-sheet-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--glass-border);
}

.answer-sheet-header h3 {
    margin: 0;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.btn-toggle {
    background: transparent;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    color: var(--text-muted);
    padding: 6px 10px;
    border-radius: var(--radius-sm);
    transition: var(--transition);
}

.btn-toggle:hover {
    background: var(--bg-input);
    color: var(--primary-color);
}

.answer-sheet-stats {
    display: flex;
    justify-content: space-between;
    margin-bottom: 16px;
    font-size: 0.9rem;
}

.stat-done {
    color: var(--success-color);
    font-weight: 500;
}

.stat-remain {
    color: var(--text-muted);
}

.answer-sheet-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 10px;
    margin-bottom: 16px;
    max-height: 320px;
    overflow-y: auto;
    padding-right: 6px;
}

/* 自定义滚动条 */
.answer-sheet-grid::-webkit-scrollbar {
    width: 4px;
}

.answer-sheet-grid::-webkit-scrollbar-track {
    background: var(--bg-input);
    border-radius: 2px;
}

.answer-sheet-grid::-webkit-scrollbar-thumb {
    background: var(--glass-border);
    border-radius: 2px;
}

.sheet-item {
    width: 100%;
    aspect-ratio: 1;
    border: 2px solid var(--glass-border);
    border-radius: var(--radius-sm);
    background: var(--bg-input);
    cursor: pointer;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.sheet-item:hover {
    border-color: var(--primary-color);
    background: rgba(102, 126, 234, 0.2);
    color: var(--text-primary);
}

.sheet-item.current {
    border-color: var(--primary-color);
    background: var(--primary-gradient);
    color: white;
    box-shadow: var(--glow-primary);
}

.sheet-item.correct {
    border-color: var(--success-color);
    background: rgba(0, 217, 165, 0.2);
    color: var(--success-color);
}

.sheet-item.wrong {
    border-color: var(--danger-color);
    background: rgba(255, 107, 107, 0.2);
    color: var(--danger-color);
}

.sheet-item.answered {
    border-color: var(--secondary-color);
    background: rgba(108, 122, 137, 0.2);
}

.answer-sheet-legend {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    font-size: 0.8rem;
    color: var(--text-muted);
    padding-top: 12px;
    border-top: 1px solid var(--glass-border);
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 6px;
}

.legend-dot {
    width: 14px;
    height: 14px;
    border-radius: 4px;
    border: 2px solid;
}

.legend-dot.current {
    border-color: var(--primary-color);
    background: var(--primary-gradient);
}

.legend-dot.correct {
    border-color: var(--success-color);
    background: rgba(0, 217, 165, 0.3);
}

.legend-dot.wrong {
    border-color: var(--danger-color);
    background: rgba(255, 107, 107, 0.3);
}

.legend-dot.unanswered {
    border-color: var(--glass-border);
    background: var(--bg-input);
}

/* 答题卡收起状态 */
.answer-sheet-sidebar.collapsed {
    width: 60px;
}

.answer-sheet-sidebar.collapsed .answer-sheet-card {
    padding: 12px;
}

.answer-sheet-sidebar.collapsed .answer-sheet-header h3,
.answer-sheet-sidebar.collapsed .answer-sheet-stats,
.answer-sheet-sidebar.collapsed .answer-sheet-grid,
.answer-sheet-sidebar.collapsed .answer-sheet-legend {
    display: none;
}

.answer-sheet-sidebar.collapsed .btn-toggle {
    transform: rotate(180deg);
}

/* ==================== 答题区域 ==================== */
.quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
}

.quiz-header h2 {
    border: none;
    padding: 0;
    margin: 0;
    font-size: 1.3rem;
}

.quiz-progress {
    font-size: 1.1rem;
    font-weight: 600;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.progress-bar {
    height: 6px;
    background: var(--bg-input);
    border-radius: 3px;
    margin-bottom: 28px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--primary-gradient);
    border-radius: 3px;
    transition: width 0.4s ease;
    width: 0%;
    box-shadow: 0 0 10px rgba(102, 126, 234, 0.5);
}

.question-container {
    margin-bottom: 28px;
    min-height: 280px;
    max-height: 400px;
    overflow-y: auto;
    padding-right: 8px;
}

.question-container::-webkit-scrollbar {
    width: 4px;
}

.question-container::-webkit-scrollbar-track {
    background: var(--bg-input);
    border-radius: 2px;
}

.question-container::-webkit-scrollbar-thumb {
    background: var(--glass-border);
    border-radius: 2px;
}

/* 移动端优化：避免内部滚动条，优先页面整体滚动 */
@media (max-width: 768px) {
    .question-container {
        min-height: auto;
        max-height: none;
        overflow-y: visible;
        padding-right: 0;
    }
}

.question-type {
    display: inline-block;
    padding: 6px 16px;
    background: var(--primary-gradient);
    color: white;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
    margin-bottom: 16px;
}

.question-text {
    font-size: 1.2rem;
    font-weight: 500;
    margin-bottom: 24px;
    line-height: 1.8;
    color: var(--text-primary);
}

/* ==================== 选项列表 ==================== */
.options-list {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.option-item {
    display: flex;
    align-items: center;
    padding: 18px 22px;
    background: var(--bg-input);
    border: 2px solid var(--glass-border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: var(--transition);
}

.option-item:hover {
    border-color: var(--primary-color);
    background: rgba(102, 126, 234, 0.1);
    transform: translateX(4px);
}

.option-item.selected {
    border-color: var(--primary-color);
    background: rgba(102, 126, 234, 0.15);
    box-shadow: 0 0 20px rgba(102, 126, 234, 0.2);
}

.option-item.correct {
    border-color: var(--success-color);
    background: rgba(0, 217, 165, 0.15);
    box-shadow: var(--glow-success);
}

.option-item.wrong {
    border-color: var(--danger-color);
    background: rgba(255, 107, 107, 0.15);
    box-shadow: var(--glow-danger);
}

.option-item input {
    margin-right: 14px;
    width: 20px;
    height: 20px;
    accent-color: var(--primary-color);
}

.option-item label {
    flex: 1;
    cursor: pointer;
    font-size: 1rem;
    color: var(--text-primary);
}

/* 填空题和简答题输入框 */
.answer-input {
    width: 100%;
    padding: 14px 18px;
    border: 2px solid var(--glass-border);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    font-family: inherit;
    background: var(--bg-input);
    color: var(--text-primary);
    transition: var(--transition);
}

.answer-input:focus {
    outline: none;
    border-color: var(--primary-color);
    background: rgba(102, 126, 234, 0.1);
}

.answer-input::placeholder {
    color: var(--text-muted);
}

textarea.answer-input {
    min-height: 140px;
    resize: vertical;
}

/* 答题操作按钮 */
.quiz-actions {
    display: flex;
    justify-content: center;
    gap: 14px;
    margin-bottom: 24px;
}

/* ==================== 答案反馈 ==================== */
.answer-feedback {
    padding: 20px 24px;
    border-radius: var(--radius-sm);
    margin-top: 24px;
    animation: slideUp 0.3s ease-out;
}

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

.answer-feedback.correct {
    background: rgba(0, 217, 165, 0.15);
    border: 2px solid var(--success-color);
    box-shadow: var(--glow-success);
}

.answer-feedback.wrong {
    background: rgba(255, 107, 107, 0.15);
    border: 2px solid var(--danger-color);
    box-shadow: var(--glow-danger);
}

.feedback-icon {
    font-size: 1.5rem;
    margin-right: 12px;
}

.feedback-text {
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.correct-answer {
    color: var(--text-secondary);
}

/* ==================== 结果页面 ==================== */
.result-card {
    text-align: center;
    padding: 40px;
}

.result-card h2 {
    border: none;
    font-size: 2.2rem;
    margin-bottom: 36px;
    justify-content: center;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.result-stats {
    display: flex;
    justify-content: center;
    gap: 50px;
    margin-bottom: 36px;
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 24px 32px;
    background: var(--bg-input);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius);
    min-width: 120px;
    transition: var(--transition);
}

.stat-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--glow-primary);
}

.stat-value {
    font-size: 2.8rem;
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-size: 1rem;
    color: var(--text-muted);
    margin-top: 8px;
    font-weight: 500;
}

.result-actions {
    display: flex;
    justify-content: center;
    gap: 16px;
}

/* ==================== 分析结果样式 ==================== */
#result-content {
    max-height: 450px;
    overflow-y: auto;
    padding-right: 10px;
}

#result-content::-webkit-scrollbar {
    width: 6px;
}

#result-content::-webkit-scrollbar-track {
    background: var(--bg-input);
    border-radius: 3px;
}

#result-content::-webkit-scrollbar-thumb {
    background: var(--glass-border);
    border-radius: 3px;
}

.question-preview {
    padding: 16px 20px;
    background: var(--bg-input);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-sm);
    margin-bottom: 12px;
    transition: var(--transition);
}

.question-preview:hover {
    border-color: var(--primary-color);
    transform: translateX(4px);
}

.question-preview .q-type {
    display: inline-block;
    padding: 4px 12px;
    background: var(--primary-gradient);
    color: white;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 500;
    margin-right: 10px;
}

.question-preview .q-text {
    font-weight: 500;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.question-preview .q-answer {
    font-size: 0.9rem;
    color: var(--success-color);
}

/* ==================== Toast 消息提示 ==================== */
.toast {
    position: fixed;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    padding: 16px 32px;
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    color: var(--text-primary);
    border-radius: var(--radius-sm);
    font-size: 0.95rem;
    font-weight: 500;
    opacity: 0;
    transition: var(--transition);
    z-index: 1000;
    max-width: 90%;
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    box-shadow: var(--glass-shadow);
}

.toast.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
}

.toast.success {
    border-color: var(--success-color);
    box-shadow: var(--glow-success);
}

.toast.error {
    border-color: var(--danger-color);
    box-shadow: var(--glow-danger);
}

.toast.warning {
    border-color: var(--warning-color);
    color: var(--warning-color);
}

/* ==================== 页脚 ==================== */
footer {
    text-align: center;
    padding: 30px;
    color: var(--text-muted);
    font-size: 0.9rem;
    border-top: 1px solid var(--glass-border);
    margin-top: 40px;
}

/* ==================== 响应式设计 ==================== */
@media (max-width: 1280px) {
    :root {
        --quiz-width: 1040px;
        --quiz-height: 700px;
    }
}

@media (max-width: 1100px) {
    :root {
        --quiz-width: 960px;
        --quiz-height: 660px;
    }
}

@media (max-width: 900px) {
    :root {
        --quiz-width: 100%;
        --quiz-height: auto;
    }
}

@media (max-width: 768px) {
    .quiz-layout {
        flex-direction: column;
        width: 100%;
        min-height: auto;
    }
    
    .answer-sheet-sidebar {
        width: 100%;
        position: static;
    }
    
    /* 移动端答题卡：移除高度限制，避免内部滚动条 */
    .answer-sheet-grid {
        grid-template-columns: repeat(8, 1fr);
        max-height: none;
        overflow-y: visible;
    }
    
    .answer-sheet-sidebar.collapsed {
        width: 100%;
    }
    
    .answer-sheet-sidebar.collapsed .answer-sheet-grid {
        display: grid;
        grid-template-columns: repeat(10, 1fr);
        max-height: none;
    }
    
    .answer-sheet-sidebar.collapsed .answer-sheet-header h3,
    .answer-sheet-sidebar.collapsed .answer-sheet-stats,
    .answer-sheet-sidebar.collapsed .answer-sheet-legend {
        display: none;
    }
}

@media (max-width: 600px) {
    .container {
        padding: 16px;
    }

    header h1 {
        font-size: 1.8rem;
    }

    .nav-btn {
        padding: 10px 20px;
        font-size: 0.9rem;
    }

    .card {
        padding: 20px;
        border-radius: var(--radius-sm);
    }

    .quiz-header {
        flex-direction: column;
        gap: 12px;
    }

    /* 移动端题目容器：移除高度限制，避免内部滚动条，优先页面整体滚动 */
    .question-container {
        min-height: auto;
        max-height: none;
        overflow-y: visible;
        padding-right: 0;
    }

    .quiz-main{
        width: 100%;
    }
    .question-text {
        font-size: 1.05rem;
        line-height: 1.7;
    }

    .option-item {
        padding: 14px 16px;
    }

    .option-item label {
        font-size: 0.95rem;
    }

    .result-stats {
        flex-direction: column;
        gap: 16px;
    }

    .stat-item {
        padding: 20px;
        min-width: auto;
        width: 100%;
    }

    .stat-value {
        font-size: 2.2rem;
    }

    .exam-item {
        flex-direction: column;
        gap: 14px;
        align-items: flex-start;
    }

    .exam-actions {
        width: 100%;
    }

    .exam-actions .btn {
        flex: 1;
    }

    .shuffle-options {
        flex-direction: column;
        gap: 14px;
    }

    .quiz-actions {
        flex-direction: column;
    }

    .quiz-actions .btn {
        width: 100%;
    }

    .result-actions {
        flex-direction: column;
    }

    .result-actions .btn {
        width: 100%;
    }
    
    /* 移动端答题卡网格：移除高度限制 */
    .answer-sheet-grid {
        max-height: none;
        overflow-y: visible;
    }
}

/* ==================== 设置页面 ==================== */
.settings-desc {
    color: var(--text-muted);
    margin-bottom: 28px;
}

#settings-page .btn {
    margin-right: 12px;
    margin-top: 12px;
}

/* ==================== 登录页面 ==================== */
.login-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.login-card {
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: 40px;
    width: 100%;
    max-width: 420px;
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    box-shadow: var(--glass-shadow);
}

.login-header {
    text-align: center;
    margin-bottom: 32px;
}

.login-header h1 {
    font-size: 1.8rem;
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 12px;
}

.login-header p {
    color: var(--text-muted);
    font-size: 0.95rem;
}

.login-form .form-group {
    margin-bottom: 20px;
}

.login-form .btn.full-width {
    width: 100%;
    padding: 14px;
    font-size: 1rem;
    margin-top: 8px;
}

.login-error {
    margin-top: 16px;
    padding: 12px;
    background: rgba(255, 107, 107, 0.1);
    border: 1px solid rgba(255, 107, 107, 0.3);
    border-radius: var(--radius-sm);
    color: var(--danger-color);
    text-align: center;
    font-size: 0.9rem;
}

/* ==================== 头部用户信息 ==================== */
.header-right {
    display: flex;
    align-items: center;
    gap: 24px;
    flex-wrap: wrap;
    justify-content: center;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 8px 16px;
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    border-radius: 50px;
}

.user-info #current-user {
    color: var(--text-primary);
    font-weight: 500;
}

.btn.small {
    padding: 6px 14px;
    font-size: 0.85rem;
}

/* ==================== 用户管理页面 ==================== */
.admin-actions {
    margin-bottom: 24px;
}

.users-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.user-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 20px;
    background: var(--bg-input);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-sm);
    transition: var(--transition);
}

.user-item:hover {
    background: var(--bg-card-hover);
    border-color: var(--primary-color);
}

.user-item-info {
    display: flex;
    align-items: center;
    gap: 12px;
}

.user-item-name {
    font-weight: 500;
    color: var(--text-primary);
}

.user-item-badge {
    padding: 4px 10px;
    font-size: 0.75rem;
    border-radius: 20px;
    background: var(--primary-gradient);
    color: white;
}

.user-item-badge.normal {
    background: var(--bg-card);
    border: 1px solid var(--glass-border);
    color: var(--text-muted);
}

.user-item-actions {
    display: flex;
    gap: 8px;
}

.user-item-actions .btn {
    padding: 6px 12px;
    font-size: 0.8rem;
}

/* ==================== 弹窗样式 ==================== */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 20px;
}

.modal-content {
    background: var(--bg-dark);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius);
    padding: 28px;
    width: 100%;
    max-width: 450px;
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
}

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 24px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--glass-border);
}

.modal-header h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.modal-close {
    background: none;
    border: none;
    color: var(--text-muted);
    font-size: 1.5rem;
    cursor: pointer;
    padding: 4px 8px;
    line-height: 1;
    transition: var(--transition);
}

.modal-close:hover {
    color: var(--danger-color);
}

.modal-actions {
    display: flex;
    gap: 12px;
    justify-content: flex-end;
    margin-top: 24px;
}

/* ==================== 响应式调整 ==================== */
@media (max-width: 768px) {
    .header-right {
        flex-direction: column;
        gap: 16px;
    }
    
    .user-info {
        order: -1;
    }
    
    .user-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 12px;
    }
    
    .user-item-actions {
        width: 100%;
    }
    
    .user-item-actions .btn {
        flex: 1;
    }
}