/* 主题色变量（默认：清新天蓝→青）。可在管理页切换配色方案，
   切换时由内联脚本在 :root 上覆盖这些变量。 */
:root {
    --primary: #36a9f0;
    --secondary: #20c6d6;
    --primary-rgb: 54, 169, 240;
    --secondary-rgb: 32, 198, 214;
}

/* 基础样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'SimHei', 'Arial Unicode MS', sans-serif;
    line-height: 1.6;
    color: #2c3e50;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    background-attachment: fixed;
    min-height: 100vh;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    position: relative;
    z-index: 1;
}

/* 头部样式 */
.header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: 20px;
    padding: 30px;
    margin-bottom: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    text-align: center;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.header h1 {
    font-size: clamp(2rem, 5vw, 3rem);
    margin-bottom: 0.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
}

.header h1 i {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.header p {
    font-size: clamp(1rem, 2.5vw, 1.2rem);
    color: #6c757d;
    margin: 0;
    font-weight: 500;
    opacity: 0.8;
}

/* 导航样式 */
.nav {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-top: 1rem;
    flex-wrap: wrap;
}

.nav-link {
    color: var(--primary);
    text-decoration: none;
    padding: 0.8rem 1.5rem;
    border-radius: 25px;
    transition: all 0.3s ease;
    font-weight: 500;
    background: rgba(var(--primary-rgb), 0.1);
    border: 1px solid rgba(var(--primary-rgb), 0.2);
    backdrop-filter: blur(10px);
}

.nav-link:hover {
    background: rgba(var(--primary-rgb), 0.2);
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(var(--primary-rgb), 0.3);
}

.nav-link.active {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    box-shadow: 0 8px 25px rgba(var(--primary-rgb), 0.4);
}

/* 主内容区域 */
.main-content {
    flex: 1;
    padding: 2rem 0;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

/* 欢迎卡片 */
.welcome-card {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: 20px;
    padding: 3rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    text-align: center;
    margin-bottom: 2rem;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.welcome-card h2 {
    font-size: clamp(1.8rem, 4vw, 2.5rem);
    margin-bottom: 1rem;
    color: #2c3e50;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.welcome-card p {
    font-size: 1.1rem;
    color: #6c757d;
    margin-bottom: 2rem;
    line-height: 1.8;
}

/* 功能特性 */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin: 2rem 0;
}

.feature {
    text-align: center;
    padding: 2rem;
    border-radius: 20px;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    transition: all 0.3s ease;
    border: 1px solid rgba(255, 255, 255, 0.3);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.feature:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.15);
}

.feature-icon {
    font-size: 3.5rem;
    margin-bottom: 1.5rem;
    display: block;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.feature h3 {
    font-size: 1.4rem;
    margin-bottom: 0.8rem;
    color: #2c3e50;
    font-weight: 600;
}

.feature p {
    color: #6c757d;
    line-height: 1.6;
}

/* 按钮样式 */
.action-buttons {
    display: flex;
    gap: 1.5rem;
    justify-content: center;
    flex-wrap: wrap;
    margin-top: 2rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 1rem 2.5rem;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    min-width: 160px;
    justify-content: center;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    box-shadow: 0 8px 25px rgba(var(--primary-rgb), 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 35px rgba(var(--primary-rgb), 0.6);
}

.btn-secondary {
    background: linear-gradient(135deg, #f093fb, #f5576c);
    color: white;
    box-shadow: 0 8px 25px rgba(240, 147, 251, 0.4);
}

.btn-secondary:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 35px rgba(240, 147, 251, 0.6);
}

.btn-success {
    background: linear-gradient(135deg, #28a745, #20c997);
    color: white;
    box-shadow: 0 8px 25px rgba(40, 167, 69, 0.4);
}

.btn-success:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 35px rgba(40, 167, 69, 0.6);
}

.btn-danger {
    background: linear-gradient(135deg, #dc3545, #c82333);
    color: white;
    box-shadow: 0 8px 25px rgba(220, 53, 69, 0.4);
}

.btn-danger:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 35px rgba(220, 53, 69, 0.6);
}

/* 测验容器 */
.quiz-container {
    max-width: 900px;
    margin: 0 auto;
}

.quiz-header {
    text-align: center;
    margin-bottom: 2rem;
    color: white;
}

.quiz-header h2 {
    font-size: clamp(1.8rem, 4vw, 2.5rem);
    margin-bottom: 0.5rem;
    font-weight: 700;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.date-display {
    font-size: 1.1rem;
    opacity: 0.9;
    background: linear-gradient(135deg, rgba(255, 152, 0, 0.15), rgba(255, 193, 7, 0.15));
    padding: 0.8rem 1.5rem;
    border-radius: 15px;
    border: 1px solid rgba(255, 152, 0, 0.3);
    backdrop-filter: blur(15px);
    box-shadow: 0 4px 15px rgba(255, 152, 0, 0.2);
    display: inline-block;
    margin-top: 1rem;
}

/* 题目卡片 */
.question-card {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: 20px;
    padding: 3rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    margin-bottom: 2rem;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.question-text h3 {
    font-size: 1.5rem;
    margin-bottom: 2rem;
    color: #2c3e50;
    line-height: 1.8;
    font-weight: 600;
}

/* 选项样式 */
.question-options {
    margin: 2rem 0;
}

.option {
    display: flex;
    align-items: center;
    margin: 1rem 0;
    padding: 1.2rem;
    border: 2px solid rgba(var(--primary-rgb), 0.2);
    border-radius: 15px;
    cursor: pointer;
    transition: all 0.3s ease;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(10px);
}

.option:hover {
    border-color: var(--primary);
    background: rgba(var(--primary-rgb), 0.05);
    transform: translateX(5px);
    box-shadow: 0 8px 25px rgba(var(--primary-rgb), 0.2);
}

.option input[type="radio"] {
    margin-right: 1rem;
    transform: scale(1.3);
    accent-color: var(--primary);
}

.option label {
    cursor: pointer;
    font-size: 1.1rem;
    flex: 1;
    font-weight: 500;
    color: #2c3e50;
}

/* 答题区域 */
.answer-section {
    margin-top: 2rem;
}

.answer-input {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.answer-input label {
    font-weight: 600;
    color: #2c3e50;
    font-size: 1.1rem;
}

.answer-input input {
    padding: 1.2rem;
    border: 2px solid rgba(var(--primary-rgb), 0.2);
    border-radius: 15px;
    font-size: 1rem;
    transition: all 0.3s ease;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
}

.answer-input input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(var(--primary-rgb), 0.1);
    transform: translateY(-2px);
}

/* 结果区域 */
.result-section {
    margin-top: 2rem;
    padding: 2rem;
    border-radius: 20px;
    background: rgba(248, 249, 250, 0.9);
    backdrop-filter: blur(15px);
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.result-message {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    text-align: center;
    padding: 1rem;
    border-radius: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.result-message.correct {
    color: #155724;
    background: linear-gradient(135deg, #d4edda, #c3e6cb);
    border: 2px solid #28a745;
}

.result-message.incorrect {
    color: #721c24;
    background: linear-gradient(135deg, #f8d7da, #f5c6cb);
    border: 2px solid #dc3545;
}

.correct-answer, .explanation {
    margin: 1rem 0;
    padding: 1.5rem;
    background: rgba(255, 255, 255, 0.9);
    border-radius: 15px;
    border-left: 4px solid var(--primary);
    backdrop-filter: blur(10px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

/* 进度页面样式 */
.progress-container {
    max-width: 1000px;
    margin: 0 auto;
}

.progress-header {
    text-align: center;
    margin-bottom: 2rem;
    color: white;
}

.progress-header h2 {
    font-size: clamp(1.8rem, 4vw, 2.5rem);
    margin-bottom: 0.5rem;
    font-weight: 700;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

/* 统计卡片 */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.stat-card {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: 20px;
    padding: 2.5rem;
    text-align: center;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.15);
}

.stat-icon {
    font-size: 3rem;
    margin-bottom: 1.5rem;
    display: block;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-content h3 {
    font-size: 1.2rem;
    color: #6c757d;
    margin-bottom: 0.8rem;
    font-weight: 500;
}

.stat-number {
    font-size: 3rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* 历史记录 */
.progress-history {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: 20px;
    padding: 2.5rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.progress-history h3 {
    font-size: 1.6rem;
    margin-bottom: 1.5rem;
    color: #2c3e50;
    font-weight: 600;
}

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

.history-item {
    display: flex;
    align-items: center;
    padding: 1.5rem;
    border-radius: 15px;
    background: rgba(248, 249, 250, 0.8);
    border-left: 4px solid #6c757d;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
}

.history-item:hover {
    transform: translateX(5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
}

.history-item.correct {
    border-left-color: #28a745;
    background: rgba(212, 237, 218, 0.8);
}

.history-item.incorrect {
    border-left-color: #dc3545;
    background: rgba(248, 215, 218, 0.8);
}

.history-date {
    font-weight: 600;
    color: #2c3e50;
    min-width: 120px;
    background: linear-gradient(135deg, rgba(255, 152, 0, 0.1), rgba(255, 193, 7, 0.1));
    padding: 0.6rem 1rem;
    border-radius: 10px;
    border: 1px solid rgba(255, 152, 0, 0.25);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 8px rgba(255, 152, 0, 0.15);
    text-align: center;
}

.history-result {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin: 0 1rem;
    min-width: 80px;
}

.result-icon {
    font-size: 1.2rem;
}

.history-details {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.user-answer, .correct-answer {
    font-size: 0.95rem;
    color: #6c757d;
    line-height: 1.4;
}

/* 空状态 */
.empty-state {
    text-align: center;
    padding: 4rem 2rem;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.empty-icon {
    font-size: 4.5rem;
    margin-bottom: 1.5rem;
    display: block;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.empty-state h3 {
    font-size: 1.6rem;
    margin-bottom: 0.8rem;
    color: #2c3e50;
    font-weight: 600;
}

.empty-state p {
    color: #6c757d;
    margin-bottom: 2rem;
    font-size: 1.1rem;
    line-height: 1.6;
}

/* 加载动画 */
.loading {
    text-align: center;
    padding: 3rem;
    color: #6c757d;
}

.spinner {
    width: 45px;
    height: 45px;
    border: 4px solid rgba(var(--primary-rgb), 0.3);
    border-top: 4px solid var(--primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 1.5rem;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* 错误消息 */
.error-message {
    text-align: center;
    padding: 2.5rem;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.error-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    display: block;
    color: #dc3545;
}

.error {
    color: #dc3545;
    font-weight: 600;
    font-size: 1.2rem;
}

/* 页脚 */
.footer {
    text-align: center;
    padding: 2rem 0;
    color: white;
    opacity: 0.9;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: 20px;
    margin-top: 2rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.footer p {
    color: #6c757d;
    margin: 0;
    font-weight: 500;
}

/* 完成状态容器样式 */
.completion-container,
.incomplete-container {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: 20px;
    padding: 50px 40px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    text-align: center;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

/* 头部样式 */
.completion-header,
.incomplete-header {
    margin-bottom: 40px;
}

.completion-icon,
.incomplete-icon {
    width: 120px;
    height: 120px;
    margin: 0 auto 25px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

.completion-icon {
    background: linear-gradient(135deg, #ffd700, #ffed4e);
    box-shadow: 0 10px 30px rgba(255, 215, 0, 0.4);
}

.incomplete-icon {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    box-shadow: 0 10px 30px rgba(var(--primary-rgb), 0.4);
}

.completion-icon i,
.incomplete-icon i {
    font-size: 3.5rem;
    color: white;
    filter: drop-shadow(0 4px 8px rgba(0, 0, 0, 0.2));
}

.completion-title,
.incomplete-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 10px;
    background: linear-gradient(135deg, #2c3e50, #34495e);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* 统计信息样式 */
.completion-stats,
.incomplete-stats {
    display: flex;
    justify-content: center;
    gap: 30px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.stat-item {
    background: rgba(255, 255, 255, 0.8);
    border-radius: 20px;
    padding: 25px 30px;
    min-width: 200px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.3);
    transition: all 0.3s ease;
}

.stat-item:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.15);
}

.stat-icon {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 15px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    box-shadow: 0 8px 20px rgba(var(--primary-rgb), 0.3);
}

.stat-icon i {
    font-size: 1.5rem;
    color: white;
}

.stat-content {
    text-align: center;
}

.stat-label {
    font-size: 0.9rem;
    color: #6c757d;
    font-weight: 600;
    margin-bottom: 5px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.stat-value {
    font-size: 1.8rem;
    font-weight: 700;
    color: #2c3e50;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* 操作按钮样式 */
.completion-actions,
.incomplete-actions {
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
}

.btn-large {
    padding: 18px 35px;
    font-size: 1.1rem;
    border-radius: 30px;
    min-width: 180px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    font-weight: 600;
    transition: all 0.3s ease;
}

.btn-large:hover {
    transform: translateY(-2px);
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.2);
}

.btn-large i {
    font-size: 1.2rem;
}

.btn-large span {
    font-weight: 600;
}

/* 简化的计时器样式 */
.timer-simple {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    margin-top: 20px;
    padding: 12px 20px;
}

.timer-simple i {
    font-size: 1.2rem;
    color: var(--primary);
}

.timer-simple span {
    font-size: 1.4rem;
    font-weight: 600;
    color: #2c3e50;
    font-family: 'Courier New', monospace;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 0 15px;
    }
    
    .header {
        padding: 25px 20px;
        margin-bottom: 15px;
    }
    
    .welcome-card {
        padding: 2rem 1.5rem;
    }
    
    .features {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .action-buttons {
        flex-direction: column;
        align-items: center;
        gap: 1rem;
    }
    
    .btn {
        width: 100%;
        max-width: 300px;
    }
    
    .question-card {
        padding: 2rem 1.5rem;
    }
    
    .question-text h3 {
        font-size: 1.3rem;
    }
    
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }
    
    .stat-card {
        padding: 2rem 1.5rem;
    }
    
    .stat-number {
        font-size: 2.5rem;
    }
    
    .history-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }
    
    .history-date {
        min-width: auto;
        align-self: flex-start;
    }
    
    .history-result {
        margin: 0;
        min-width: auto;
        align-self: flex-start;
    }
    
    .nav {
        gap: 1rem;
    }
    
    .nav-link {
        padding: 0.6rem 1.2rem;
        font-size: 0.9rem;
    }

    .completion-container,
    .incomplete-container {
        padding: 40px 25px;
        margin: 20px;
    }
    
    .completion-title,
    .incomplete-title {
        font-size: 2rem;
    }
    
    .completion-stats,
    .incomplete-stats {
        flex-direction: column;
        align-items: center;
    }
    
    .stat-item {
        min-width: 180px;
        padding: 20px 25px;
    }
    
    .completion-actions,
    .incomplete-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .btn-large {
        width: 100%;
        max-width: 300px;
    }
}

@media (max-width: 480px) {
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .question-card {
        padding: 1.5rem 1rem;
    }
    
    .welcome-card {
        padding: 1.5rem 1rem;
    }
    
    .header h1 {
        font-size: 1.8rem;
    }
    
    .header p {
        font-size: 1rem;
    }
    
    .btn {
        padding: 0.8rem 2rem;
        font-size: 0.95rem;
    }
    
    .stat-card {
        padding: 1.5rem 1rem;
    }
    
    .progress-history {
        padding: 1.5rem 1rem;
    }
    
    .empty-state {
        padding: 2rem 1rem;
    }
    
    .empty-icon {
        font-size: 3.5rem;
    }
    
    .empty-state h3 {
        font-size: 1.4rem;
    }

    .completion-container,
    .incomplete-container {
        padding: 30px 20px;
    }
    
    .completion-icon,
    .incomplete-icon {
        width: 100px;
        height: 100px;
    }
    
    .completion-icon i,
    .incomplete-icon i {
        font-size: 3rem;
    }
    
    .completion-title,
    .incomplete-title {
        font-size: 1.8rem;
    }
    
    .stat-item {
        min-width: 160px;
        padding: 15px 20px;
    }
    
    .stat-value {
        font-size: 1.5rem;
    }
}

/* 触摸设备优化 */
@media (hover: none) and (pointer: coarse) {
    .btn:hover {
        transform: none;
    }
    
    .btn:active {
        transform: scale(0.98);
    }
    
    .feature:hover {
        transform: none;
    }
    
    .feature:active {
        transform: scale(0.98);
    }
    
    .history-item:hover {
        transform: none;
    }
    
    .history-item:active {
        transform: scale(0.98);
    }
    
    .option:hover {
        transform: none;
    }
    
    .option:active {
        transform: scale(0.98);
    }
}

/* 高分辨率屏幕优化 */
@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
    .header, .welcome-card, .question-card, .stat-card, .progress-history, .empty-state, .error-message, .footer {
        border-width: 0.5px;
    }
}

/* 横屏模式优化 */
@media (orientation: landscape) and (max-height: 500px) {
    .header {
        padding: 15px 20px;
        margin-bottom: 10px;
    }
    
    .header h1 {
        font-size: 1.5rem;
        margin-bottom: 5px;
    }
    
    .welcome-card {
        padding: 1.5rem;
    }
    
    .question-card {
        padding: 1.5rem;
    }
    
    .action-buttons {
        flex-direction: row;
        gap: 1rem;
    }
    
    .btn {
        width: auto;
        max-width: none;
    }
}