/* ==========================================================================
   DMD课程网站样式表
   参考顶级学府设计风格 - 现代化、专业、清晰
   ========================================================================== */

/* 基础重置和全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* 清华紫色系调色板 - 基于PANTONE 259C优化 */
    --primary-color: #6B4C93;        /* 主紫色 - 优雅深紫 */
    --primary-light: #8B6FB0;        /* 浅主紫色 */
    --primary-dark: #4A2B6B;         /* 深主紫色 */
    --secondary-color: #9C7AB8;      /* 次紫色 - 中等紫色 */
    --accent-color: #B794C7;         /* 强调色 - 浅紫色 */
    --tertiary-color: #5D4E6F;       /* 第三色 - 紫灰色 */
    
    /* 紫色渐变系列 */
    --purple-50: #F8F5FC;           /* 极浅紫 - 背景使用 */
    --purple-100: #E8DDF0;          /* 很浅紫 - 卡片背景 */
    --purple-200: #D4BFE3;          /* 浅紫 - 分割线 */
    --purple-300: #B794C7;          /* 中浅紫 - 辅助元素 */
    --purple-400: #9C7AB8;          /* 中紫 - 次要按钮 */
    --purple-500: #8B6FB0;          /* 标准紫 - 主要元素 */
    --purple-600: #6B4C93;          /* 深紫 - 主色调 */
    --purple-700: #5D4080;          /* 更深紫 - 强调 */
    --purple-800: #4A2B6B;          /* 很深紫 - 深色背景 */
    --purple-900: #3A1F52;          /* 极深紫 - 文字 */
    
    /* 辅助色彩 */
    --success-color: #7C3AED;        /* 成功色 - 紫色调 */
    --warning-color: #A855F7;        /* 警告色 - 亮紫色 */
    --error-color: #C084FC;          /* 错误色 - 粉紫色 */
    
    /* 中性色系 - 调整为配合紫色 */
    --gray-50: #FDFCFE;             /* 微紫白色 */
    --gray-100: #F7F5F9;            /* 浅紫灰 */
    --gray-200: #E9E5ED;            /* 紫灰色 */
    --gray-300: #D6CDD9;            /* 中紫灰 */
    --gray-400: #B8ACB8;            /* 深紫灰 */
    --gray-500: #8B7D8B;            /* 紫调灰 */
    --gray-600: #6B5F6B;            /* 深紫调灰 */
    --gray-700: #4B404B;            /* 很深紫灰 */
    --gray-800: #2D242D;            /* 极深紫灰 */
    --gray-900: #1A141A;            /* 近黑紫 */
    
    /* 字体系统 */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-serif: 'Times New Roman', serif;
    
    /* 间距系统 */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    
    /* 阴影系统 - 调整为紫色调 */
    --shadow-sm: 0 1px 2px 0 rgba(107, 76, 147, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(107, 76, 147, 0.1), 0 2px 4px -1px rgba(107, 76, 147, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(107, 76, 147, 0.1), 0 4px 6px -2px rgba(107, 76, 147, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(107, 76, 147, 0.1), 0 10px 10px -5px rgba(107, 76, 147, 0.04);
    
    /* 渐变定义 */
    --gradient-primary: linear-gradient(135deg, var(--purple-600) 0%, var(--purple-700) 100%);
    --gradient-secondary: linear-gradient(135deg, var(--purple-400) 0%, var(--purple-600) 100%);
    --gradient-accent: linear-gradient(135deg, var(--purple-300) 0%, var(--purple-500) 100%);
    --gradient-subtle: linear-gradient(135deg, var(--purple-50) 0%, var(--purple-100) 100%);
    
    /* 边框圆角 */
    --radius-sm: 0.25rem;
    --radius-md: 0.375rem;
    --radius-lg: 0.5rem;
    --radius-xl: 0.75rem;
    --radius-2xl: 1rem;
}

/* 基础样式 */
html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-primary);
    line-height: 1.6;
    color: var(--gray-700);
    background-color: #ffffff;
    overflow-x: hidden;
}

/* 容器样式 */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* 按钮样式 */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: 0.75rem 1.5rem;
    font-weight: 500;
    text-decoration: none;
    border-radius: var(--radius-lg);
    transition: all 0.2s ease;
    border: none;
    cursor: pointer;
    font-size: 0.875rem;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    border: none;
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--purple-700) 0%, var(--purple-800) 100%);
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: white;
    color: var(--purple-600);
    border: 1px solid var(--purple-300);
}

.btn-secondary:hover {
    background: var(--purple-50);
    border-color: var(--purple-400);
    color: var(--purple-700);
    transform: translateY(-1px);
}

/* ==========================================================================
   导航栏样式
   ========================================================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--purple-200);
    z-index: 1000;
    transition: all 0.3s ease;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.university-logo {
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.1));
}

.brand-text {
    display: flex;
    flex-direction: column;
}

.university {
    font-weight: 700;
    font-size: 1.1rem;
    color: var(--primary-color);
    line-height: 1.2;
}

.program {
    font-size: 0.75rem;
    color: var(--purple-500);
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-xl);
    margin: 0;
}

.nav-link {
    text-decoration: none;
    color: var(--purple-600);
    font-weight: 500;
    font-size: 0.9rem;
    transition: color 0.2s ease;
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-color);
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--gradient-primary);
    border-radius: 1px;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 4px;
}

.nav-toggle span {
    width: 25px;
    height: 2px;
    background-color: var(--purple-600);
    border-radius: 1px;
    transition: all 0.3s ease;
}

/* ==========================================================================
   英雄区域样式
   ========================================================================== */
.hero {
    padding: 120px 0 80px;
    background: var(--gradient-subtle);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns=\"http://www.w3.org/2000/svg\" viewBox=\"0 0 1000 1000\"><defs><pattern id=\"grain\" width=\"100\" height=\"100\" patternUnits=\"userSpaceOnUse\"><circle cx=\"50\" cy=\"50\" r=\"1\" fill=\"%236B4C93\" opacity=\"0.05\"/></pattern></defs><rect width=\"100%\" height=\"100%\" fill=\"url(%23grain)\"/></svg>');
    opacity: 0.6;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-3xl);
    align-items: center;
    position: relative;
    z-index: 2;
}

.hero-content {
    z-index: 2;
}

.hero-badge {
    display: inline-block;
    margin-bottom: var(--spacing-lg);
}

.hero-badge span {
    background: var(--gradient-primary);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-xl);
    font-size: 0.8rem;
    font-weight: 500;
    letter-spacing: 0.05em;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    line-height: 1.1;
    color: var(--purple-900);
    margin-bottom: var(--spacing-lg);
}

.subtitle {
    display: block;
    font-size: 1.5rem;
    font-weight: 400;
    color: var(--purple-700);
    margin-top: var(--spacing-sm);
    font-style: italic;
}

.hero-description {
    font-size: 1.1rem;
    color: var(--purple-600);
    margin-bottom: var(--spacing-xl);
    line-height: 1.7;
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

.hero-stats {
    display: flex;
    gap: var(--spacing-2xl);
}

.stat {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    line-height: 1;
}

.stat-label {
    font-size: 0.9rem;
    color: var(--purple-500);
    margin-top: var(--spacing-xs);
}

.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.data-visualization {
    background: white;
    border-radius: var(--radius-2xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-xl);
    transform: rotate(2deg);
    transition: transform 0.3s ease;
}

.data-visualization:hover {
    transform: rotate(0deg) scale(1.02);
}

.chart-title {
    font-size: 0.9rem;
    font-weight: 600;
    fill: var(--gray-700);
}

.chart-lines path {
    animation: drawLine 2s ease-in-out;
}

.chart-points circle {
    animation: fadeInPoint 0.5s ease-in-out;
    animation-fill-mode: both;
}

.chart-points circle:nth-child(1) { animation-delay: 0.2s; }
.chart-points circle:nth-child(2) { animation-delay: 0.4s; }
.chart-points circle:nth-child(3) { animation-delay: 0.6s; }
.chart-points circle:nth-child(4) { animation-delay: 0.8s; }
.chart-points circle:nth-child(5) { animation-delay: 1.0s; }

/* ==========================================================================
   通用区域样式
   ========================================================================== */
.section-header {
    text-align: center;
    margin-bottom: var(--spacing-3xl);
}

.section-header h2 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: var(--spacing-md);
}

.section-header p {
    font-size: 1.1rem;
    color: var(--gray-600);
    max-width: 600px;
    margin: 0 auto;
}

/* ==========================================================================
   课程概览样式
   ========================================================================== */
.course-overview {
    padding: var(--spacing-3xl) 0;
    background-color: white;
}

.overview-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-xl);
}

.overview-card {
    background: white;
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
    border: 1px solid var(--purple-100);
}

.overview-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
    border-color: var(--purple-200);
}

.card-icon {
    width: 60px;
    height: 60px;
    background: var(--gradient-primary);
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--spacing-lg);
    color: white;
    font-size: 1.5rem;
}

.overview-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--purple-900);
    margin-bottom: var(--spacing-md);
}

.overview-card p {
    color: var(--purple-600);
    line-height: 1.6;
}

/* ==========================================================================
   教学日历样式
   ========================================================================== */
.syllabus {
    padding: var(--spacing-3xl) 0;
    background: white;
}

.schedule-table-wrapper {
    margin: var(--spacing-2xl) 0;
    background: white;
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.schedule-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
}

.schedule-table thead {
    background: var(--gradient-primary);
    color: white;
}

.schedule-table th {
    padding: var(--spacing-lg) var(--spacing-md);
    text-align: left;
    font-weight: 600;
    font-size: 0.875rem;
    letter-spacing: 0.025em;
}

.schedule-table th:first-child {
    width: 60px;
    text-align: center;
}

.schedule-table th:nth-child(2) {
    width: 140px;
}

.schedule-table th:nth-child(3) {
    width: 35%;
}

.schedule-table th:nth-child(4) {
    width: 40%;
}

.schedule-table tbody tr {
    border-bottom: 1px solid var(--purple-100);
    transition: background-color 0.2s ease;
}

.schedule-table tbody tr:hover {
    background-color: var(--purple-50);
}

.schedule-table tbody tr:last-child {
    border-bottom: none;
}

.schedule-table td {
    padding: var(--spacing-lg) var(--spacing-md);
    vertical-align: top;
}

.schedule-table td:first-child {
    text-align: center;
    font-weight: 600;
    color: var(--primary-color);
    background-color: var(--purple-50);
}

.no-class {
    color: var(--gray-400);
    font-style: italic;
    text-align: center;
}

.offline-class {
    background-color: var(--purple-50);
    border-left: 3px solid var(--primary-color);
    padding-left: calc(var(--spacing-md) + 3px) !important;
}

.class-time {
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: var(--spacing-xs);
}

.time-detail {
    font-size: 0.8rem;
    color: var(--gray-600);
    margin-bottom: var(--spacing-xs);
}

.class-topic {
    font-size: 0.85rem;
    color: var(--gray-700);
    font-weight: 500;
}

.exam-row {
    background-color: var(--purple-100) !important;
}

.exam-row:hover {
    background-color: var(--purple-200) !important;
}

.exam-info {
    background-color: transparent !important;
    border-left: 3px solid var(--error-color);
    padding-left: calc(var(--spacing-md) + 3px) !important;
}

.exam-info .class-time {
    color: var(--error-color);
}

.schedule-summary {
    margin-top: var(--spacing-2xl);
    text-align: center;
}

.schedule-summary h3 {
    font-size: 1.25rem;
    color: var(--primary-color);
    margin-bottom: var(--spacing-lg);
    font-weight: 600;
}

.summary-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: var(--spacing-lg);
    max-width: 600px;
    margin: 0 auto;
}

.summary-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-lg);
    background: white;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: transform 0.2s ease;
}

.summary-item:hover {
    transform: translateY(-2px);
}

.summary-number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    line-height: 1;
}

.summary-label {
    font-size: 0.875rem;
    color: var(--gray-600);
    font-weight: 500;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .schedule-table-wrapper {
        margin: var(--spacing-lg) -var(--spacing-lg);
        border-radius: 0;
    }
    
    .schedule-table {
        font-size: 0.8rem;
    }
    
    .schedule-table th,
    .schedule-table td {
        padding: var(--spacing-sm);
    }
    
    .schedule-table th:nth-child(2),
    .schedule-table th:nth-child(3) {
        width: auto;
    }
    
    .summary-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
}

@media (max-width: 480px) {
    .schedule-table {
        font-size: 0.75rem;
    }
    
    .class-time {
        font-size: 0.8rem;
    }
    
    .time-detail {
        font-size: 0.7rem;
    }
    
    .class-topic {
        font-size: 0.75rem;
    }
}

/* ==========================================================================
   学习资源样式
   ========================================================================== */
.resources {
    padding: var(--spacing-3xl) 0;
    background: var(--purple-50);
}

.resources-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-xl);
}

.resource-card {
    background: white;
    border: 2px solid var(--purple-200);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    text-align: center;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.resource-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(107, 76, 147, 0.1), transparent);
    transition: left 0.5s ease;
}

.resource-card:hover::before {
    left: 100%;
}

.resource-card:hover {
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.resource-icon {
    width: 70px;
    height: 70px;
    background: var(--gradient-secondary);
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--spacing-lg);
    color: white;
    font-size: 1.75rem;
}

.resource-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--purple-900);
    margin-bottom: var(--spacing-sm);
}

.resource-card p {
    color: var(--purple-600);
    margin-bottom: var(--spacing-lg);
    line-height: 1.6;
}

.resource-link {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.2s ease;
}

.resource-link:hover {
    color: var(--purple-700);
    transform: translateX(2px);
}

/* ==========================================================================
   公告样式
   ========================================================================== */
.announcements {
    padding: var(--spacing-3xl) 0;
    background: var(--purple-50);
}

.announcements-list {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

.announcement-item {
    background: white;
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--purple-200);
    display: flex;
    gap: var(--spacing-lg);
    transition: all 0.3s ease;
}

.announcement-item:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.announcement-date {
    text-align: center;
    flex-shrink: 0;
    background: var(--gradient-primary);
    color: white;
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    min-width: 80px;
}

.date-day {
    display: block;
    font-size: 1.5rem;
    font-weight: 700;
    line-height: 1;
}

.date-month {
    display: block;
    font-size: 0.8rem;
    opacity: 0.9;
    margin-top: 2px;
}

.announcement-content {
    flex: 1;
}

.announcement-content h3 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--purple-900);
    margin-bottom: var(--spacing-sm);
}

.announcement-content p {
    color: var(--purple-600);
    line-height: 1.6;
    margin-bottom: var(--spacing-md);
}

.announcement-tag {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-md);
    font-size: 0.75rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    background: var(--warning-color);
    color: white;
}

/* ==========================================================================
   联系信息样式
   ========================================================================== */
.contact {
    padding: var(--spacing-3xl) 0;
    background: var(--gray-50);
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
}

.contact-info {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
}

.contact-info h2 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--purple-900);
    margin-bottom: var(--spacing-md);
}

.contact-info > p {
    color: var(--purple-600);
    margin-bottom: var(--spacing-xl);
    line-height: 1.6;
}

.contact-item {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.contact-item i {
    width: 20px;
    color: var(--primary-color);
    margin-top: 2px;
    flex-shrink: 0;
}

.contact-item h4 {
    font-weight: 600;
    color: var(--purple-900);
    margin-bottom: var(--spacing-xs);
}

.contact-item p {
    color: var(--purple-600);
}

.contact-form {
    background: var(--purple-50);
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    border: 1px solid var(--purple-200);
}

.contact-form h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--purple-900);
    margin-bottom: var(--spacing-xl);
}

.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-group label {
    display: block;
    font-weight: 500;
    color: var(--purple-700);
    margin-bottom: var(--spacing-sm);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--purple-300);
    border-radius: var(--radius-lg);
    font-size: 0.9rem;
    transition: all 0.2s ease;
    background: white;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(107, 76, 147, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

/* ==========================================================================
   页脚样式
   ========================================================================== */
.footer {
    background: var(--purple-900);
    padding: var(--spacing-xl) 0;
    color: white;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-lg);
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    font-weight: 500;
}

.footer-links {
    display: flex;
    gap: var(--spacing-xl);
}

.footer-links a {
    color: var(--purple-300);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.2s ease;
}

.footer-links a:hover {
    color: white;
}

.footer-copyright p {
    color: var(--purple-400);
    font-size: 0.85rem;
}

/* ==========================================================================
   动画效果
   ========================================================================== */
@keyframes drawLine {
    from {
        stroke-dasharray: 1000;
        stroke-dashoffset: 1000;
    }
    to {
        stroke-dasharray: 1000;
        stroke-dashoffset: 0;
    }
}

@keyframes fadeInPoint {
    from {
        opacity: 0;
        transform: scale(0);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ==========================================================================
   响应式设计
   ========================================================================== */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
        gap: var(--spacing-xl);
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .hero-stats {
        justify-content: center;
    }
    
    .overview-grid,
    .resources-grid {
        grid-template-columns: 1fr;
    }
    
    .timeline-item {
        flex-direction: column;
        align-items: center;
        text-align: center;
    }
    
    .contact-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-xl);
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
    
    .section-header h2 {
        font-size: 2rem;
    }
    
    .container {
        padding: 0 var(--spacing-md);
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .subtitle {
        font-size: 1.1rem;
    }
    
    .nav-container {
        padding: 0 var(--spacing-md);
    }
    
    .hero {
        padding: 100px 0 60px;
    }
    
    .timeline-marker {
        width: 50px;
        height: 50px;
        font-size: 1rem;
    }
}

/* 深色模式支持 */
@media (prefers-color-scheme: dark) {
    /* 可以在这里添加深色模式样式 */
}

/* 打印样式 */
@media print {
    .navbar,
    .nav-toggle,
    .hero-buttons,
    .footer {
        display: none;
    }
    
    body {
        font-size: 12pt;
        line-height: 1.4;
    }
    
    .hero {
        padding: 20pt 0;
    }
    
    .section-header h2 {
        font-size: 18pt;
    }
}