@charset "UTF-8";

/* CSS Reset */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* 色彩系统 - 单色调 */
    --color-primary: #000000;
    --color-secondary: #333333;
    --color-tertiary: #666666;
    --color-quaternary: #999999;
    --color-background: #ffffff;
    --color-surface: #f5f5f5;
    --color-border: #e0e0e0;
    --color-accent: #000000;

    /* 深色主题 */
    --color-primary-dark: #ffffff;
    --color-secondary-dark: #e0e0e0;
    --color-tertiary-dark: #b0b0b0;
    --color-quaternary-dark: #808080;
    --color-background-dark: #0a0a0a;
    --color-surface-dark: #1a1a1a;
    --color-border-dark: #2a2a2a;
    --color-accent-dark: #ffffff;

    /* 间距系统 */
    --spacing-unit: 8px;
    --spacing-xs: calc(var(--spacing-unit) * 0.5);
    --spacing-sm: calc(var(--spacing-unit) * 1);
    --spacing-md: calc(var(--spacing-unit) * 2);
    --spacing-lg: calc(var(--spacing-unit) * 3);
    --spacing-xl: calc(var(--spacing-unit) * 4);
    --spacing-2xl: calc(var(--spacing-unit) * 6);
    --spacing-3xl: calc(var(--spacing-unit) * 8);
    --spacing-4xl: calc(var(--spacing-unit) * 12);

    /* 字体系统 */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    --font-size-4xl: 2.5rem;
    --font-size-5xl: 3rem;

    /* 行高 */
    --line-height-tight: 1.25;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.75;

    /* 边框 */
    --border-width: 1px;
    --border-radius-sm: 2px;
    --border-radius-md: 4px;
    --border-radius-lg: 8px;

    /* 动画 */
    --transition-fast: 120ms;
    --transition-normal: 240ms;
    --transition-slow: 480ms;
    --ease: cubic-bezier(0.4, 0, 0.2, 1);

    /* 当前主题变量 */
    --current-color-primary: var(--color-primary);
    --current-color-secondary: var(--color-secondary);
    --current-color-tertiary: var(--color-tertiary);
    --current-color-background: var(--color-background);
    --current-color-surface: var(--color-surface);
    --current-color-border: var(--color-border);
    --current-color-accent: var(--color-accent);
}

/* 深色主题 */
body.dark-theme {
    --current-color-primary: var(--color-primary-dark);
    --current-color-secondary: var(--color-secondary-dark);
    --current-color-tertiary: var(--color-tertiary-dark);
    --current-color-background: var(--color-background-dark);
    --current-color-surface: var(--color-surface-dark);
    --current-color-border: var(--color-border-dark);
    --current-color-accent: var(--color-accent-dark);
}

/* 基础样式 */
html {
    font-size: 16px;
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

body {
    font-family: var(--font-family);
    line-height: var(--line-height-normal);
    color: var(--current-color-primary);
    background-color: var(--current-color-background);
    transition: background-color var(--transition-normal) var(--ease),
        color var(--transition-normal) var(--ease);
    min-height: 100vh;
    overflow-x: hidden;
}

::selection {
    background-color: var(--current-color-primary);
    color: var(--current-color-background);
}

/* 线条装饰背景 */
.lines-bg {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: -1;
    overflow: hidden;
    pointer-events: none;
}

.lines-bg::before,
.lines-bg::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    opacity: 0.03;
}

.lines-bg::before {
    background-image:
        linear-gradient(90deg, transparent 95%, var(--current-color-primary) 100%),
        linear-gradient(0deg, transparent 95%, var(--current-color-primary) 100%);
    background-size: 40px 40px;
}

.lines-bg::after {
    background-image:
        linear-gradient(45deg, transparent 94%, var(--current-color-primary) 96%),
        linear-gradient(-45deg, transparent 94%, var(--current-color-primary) 96%);
    background-size: 56px 56px;
}

/* 容器 */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-xl);
}

.container-narrow {
    max-width: 800px;
}

/* 工具类 */
.text-center {
    text-align: center;
}

.text-right {
    text-align: right;
}

.hidden {
    display: none !important;
}

.flex {
    display: flex;
}

.flex-col {
    flex-direction: column;
}

.items-center {
    align-items: center;
}

.justify-center {
    justify-content: center;
}

.justify-between {
    justify-content: space-between;
}

.gap-xs {
    gap: var(--spacing-xs);
}

.gap-sm {
    gap: var(--spacing-sm);
}

.gap-md {
    gap: var(--spacing-md);
}

.gap-lg {
    gap: var(--spacing-lg);
}

.gap-xl {
    gap: var(--spacing-xl);
}

.w-full {
    width: 100%;
}

.h-full {
    height: 100%;
}

.mt-xs {
    margin-top: var(--spacing-xs);
}

.mt-sm {
    margin-top: var(--spacing-sm);
}

.mt-md {
    margin-top: var(--spacing-md);
}

.mt-lg {
    margin-top: var(--spacing-lg);
}

.mt-xl {
    margin-top: var(--spacing-xl);
}

.mt-2xl {
    margin-top: var(--spacing-2xl);
}

.mt-3xl {
    margin-top: var(--spacing-3xl);
}

.mt-4xl {
    margin-top: var(--spacing-4xl);
}

.mb-xs {
    margin-bottom: var(--spacing-xs);
}

.mb-sm {
    margin-bottom: var(--spacing-sm);
}

.mb-md {
    margin-bottom: var(--spacing-md);
}

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

.mb-xl {
    margin-bottom: var(--spacing-xl);
}

.mb-2xl {
    margin-bottom: var(--spacing-2xl);
}

.py-sm {
    padding-top: var(--spacing-sm);
    padding-bottom: var(--spacing-sm);
}

.py-md {
    padding-top: var(--spacing-md);
    padding-bottom: var(--spacing-md);
}

.py-lg {
    padding-top: var(--spacing-lg);
    padding-bottom: var(--spacing-lg);
}

.py-xl {
    padding-top: var(--spacing-xl);
    padding-bottom: var(--spacing-xl);
}

.px-sm {
    padding-left: var(--spacing-sm);
    padding-right: var(--spacing-sm);
}

.px-md {
    padding-left: var(--spacing-md);
    padding-right: var(--spacing-md);
}

.px-lg {
    padding-left: var(--spacing-lg);
    padding-right: var(--spacing-lg);
}

/* 排版 */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-weight: 600;
    line-height: var(--line-height-tight);
    color: var(--current-color-primary);
}

h1 {
    font-size: var(--font-size-5xl);
    font-weight: 700;
    letter-spacing: -0.02em;
}

h2 {
    font-size: var(--font-size-3xl);
    margin-bottom: var(--spacing-lg);
    position: relative;
    padding-bottom: var(--spacing-md);
}

h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 48px;
    height: 2px;
    background-color: var(--current-color-primary);
}

.text-center h2::after {
    left: 50%;
    transform: translateX(-50%);
}

h3 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-sm);
}

p {
    margin-bottom: var(--spacing-md);
    color: var(--current-color-secondary);
    line-height: var(--line-height-relaxed);
}

a {
    color: inherit;
    text-decoration: none;
    transition: color var(--transition-fast) var(--ease);
    position: relative;
}

a:hover {
    color: var(--current-color-primary);
}

a::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 1px;
    background-color: var(--current-color-primary);
    transition: width var(--transition-normal) var(--ease);
}

a:hover::after {
    width: 100%;
}

hr {
    border: none;
    height: 1px;
    background-color: var(--current-color-border);
    margin: var(--spacing-2xl) 0;
}

/* 导航栏 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background-color: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: var(--border-width) solid var(--current-color-border);
    transition: all var(--transition-normal) var(--ease);
}

body.dark-theme .navbar {
    background-color: rgba(10, 10, 10, 0.9);
}

.navbar-container {
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    font-weight: 700;
    font-size: var(--font-size-xl);
    color: var(--current-color-primary);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.logo i {
    font-size: var(--font-size-2xl);
}

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

.nav-link {
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--current-color-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

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

.theme-toggle {
    background: none;
    border: none;
    width: 40px;
    height: 40px;
    border-radius: var(--border-radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--current-color-tertiary);
    transition: all var(--transition-fast) var(--ease);
    border: var(--border-width) solid var(--current-color-border);
}

.theme-toggle:hover {
    color: var(--current-color-primary);
    border-color: var(--current-color-primary);
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    width: 40px;
    height: 40px;
    border-radius: var(--border-radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--current-color-tertiary);
    transition: all var(--transition-fast) var(--ease);
    border: var(--border-width) solid var(--current-color-border);
}

.mobile-menu-btn:hover {
    color: var(--current-color-primary);
    border-color: var(--current-color-primary);
}

/* 英雄区域 */
.hero-section {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 80px;
}

.hero-content {
    max-width: 800px;
}

.hero-title {
    margin-bottom: var(--spacing-lg);
}

.hero-subtitle {
    font-size: var(--font-size-2xl);
    color: var(--current-color-secondary);
    margin-bottom: var(--spacing-xl);
    font-weight: 400;
}

.hero-description {
    font-size: var(--font-size-lg);
    max-width: 600px;
    margin-bottom: var(--spacing-2xl);
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

/* 按钮 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--border-radius-md);
    font-weight: 500;
    font-size: var(--font-size-sm);
    text-decoration: none;
    transition: all var(--transition-fast) var(--ease);
    border: var(--border-width) solid var(--current-color-primary);
    background: none;
    color: var(--current-color-primary);
    cursor: pointer;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.btn:hover {
    background-color: var(--current-color-primary);
    color: var(--current-color-background);
    transform: translateY(-2px);
}

.btn-secondary {
    border-color: var(--current-color-border);
    color: var(--current-color-tertiary);
}

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

.btn-outline {
    border-color: var(--current-color-border);
    color: var(--current-color-tertiary);
}

.btn-outline:hover {
    border-color: var(--current-color-primary);
    color: var(--current-color-primary);
    background-color: transparent;
}

/* 部分样式 */
.section {
    padding: var(--spacing-4xl) 0;
}

.section-title {
    margin-bottom: var(--spacing-2xl);
}

/* 网格布局 */
.grid {
    display: grid;
    gap: var(--spacing-xl);
}

.grid-cols-2 {
    grid-template-columns: repeat(2, 1fr);
}

.grid-cols-3 {
    grid-template-columns: repeat(3, 1fr);
}

.grid-cols-4 {
    grid-template-columns: repeat(4, 1fr);
}

/* 卡片 */
.card {
    background-color: var(--current-color-surface);
    border: var(--border-width) solid var(--current-color-border);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-xl);
    transition: all var(--transition-normal) var(--ease);
    position: relative;
    overflow: hidden;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background-color: var(--current-color-primary);
    transform: scaleX(0);
    transition: transform var(--transition-normal) var(--ease);
}

.card:hover {
    transform: translateY(-4px);
    border-color: var(--current-color-primary);
}

.card:hover::before {
    transform: scaleX(1);
}

.card-icon {
    font-size: var(--font-size-3xl);
    margin-bottom: var(--spacing-lg);
    display: inline-block;
}

.card-title {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-md);
}

.card-description {
    font-size: var(--font-size-sm);
    color: var(--current-color-tertiary);
    line-height: var(--line-height-relaxed);
}

/* 时间线 */
.timeline {
    position: relative;
    padding-left: var(--spacing-lg);
}

.timeline::before {
    content: '';
    position: absolute;
    left: 25px;
    top: 0;
    bottom: 0;
    width: 2px;
    background-color: var(--current-color-border);
}

.timeline-item {
    position: relative;
    padding-bottom: var(--spacing-2xl);
    padding-left: var(--spacing-xl);
}

.timeline-item:last-child {
    padding-bottom: 0;
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -6px;
    top: 0;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background-color: var(--current-color-primary);
    border: 2px solid var(--current-color-background);
}

.timeline-date {
    font-size: var(--font-size-sm);
    color: var(--current-color-tertiary);
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
}

.timeline-title {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-xs);
}

.timeline-description {
    font-size: var(--font-size-sm);
    color: var(--current-color-tertiary);
}

/* 项目展示 */
.project-grid {
    display: grid;
    gap: var(--spacing-xl);
}

.project-card {
    border-bottom: var(--border-width) solid var(--current-color-border);
    padding-bottom: var(--spacing-xl);
    transition: all var(--transition-normal) var(--ease);
}

.project-card:hover {
    border-color: var(--current-color-primary);
}

.project-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--spacing-md);
}

.project-year {
    font-size: var(--font-size-sm);
    color: var(--current-color-tertiary);
    font-weight: 500;
}

.project-title {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-sm);
}

.project-description {
    font-size: var(--font-size-base);
    color: var(--current-color-secondary);
    margin-bottom: var(--spacing-lg);
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.tech-tag {
    padding: var(--spacing-xs) var(--spacing-sm);
    border: var(--border-width) solid var(--current-color-border);
    border-radius: var(--border-radius-sm);
    font-size: var(--font-size-xs);
    color: var(--current-color-tertiary);
    transition: all var(--transition-fast) var(--ease);
}

.project-card:hover .tech-tag {
    border-color: var(--current-color-primary);
    color: var(--current-color-primary);
}

/* 技能展示 */
.skill-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.skill-item {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.skill-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.skill-name {
    font-weight: 500;
    font-size: var(--font-size-base);
}

.skill-level {
    font-size: var(--font-size-sm);
    color: var(--current-color-tertiary);
}

.skill-bar {
    height: 4px;
    background-color: var(--current-color-border);
    border-radius: var(--border-radius-sm);
    overflow: hidden;
}

.skill-progress {
    height: 100%;
    background-color: var(--current-color-primary);
    border-radius: var(--border-radius-sm);
    transition: width var(--transition-slow) var(--ease);
}

/* 联系方式 */
.contact-methods {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-2xl);
}

.contact-method {
    text-align: center;
    padding: var(--spacing-xl);
    border: var(--border-width) solid var(--current-color-border);
    border-radius: var(--border-radius-lg);
    transition: all var(--transition-normal) var(--ease);
}

.contact-method:hover {
    border-color: var(--current-color-primary);
    transform: translateY(-4px);
}

.contact-icon {
    font-size: var(--font-size-3xl);
    margin-bottom: var(--spacing-lg);
    display: inline-block;
}

.contact-title {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-sm);
}

.contact-detail {
    font-size: var(--font-size-sm);
    color: var(--current-color-tertiary);
}

.contact-detail a {
    color: inherit;
}

/* 微信二维码弹窗 */
.wechat-modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal) var(--ease);
    backdrop-filter: blur(4px);
}

.wechat-modal.active {
    opacity: 1;
    visibility: visible;
}

.wechat-modal-content {
    background-color: var(--current-color-background);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-2xl);
    max-width: 400px;
    width: 90%;
    position: relative;
    transform: translateY(20px);
    transition: transform var(--transition-normal) var(--ease);
    border: var(--border-width) solid var(--current-color-border);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

.wechat-modal.active .wechat-modal-content {
    transform: translateY(0);
}

.wechat-modal-close {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background-color: var(--current-color-surface);
    border: var(--border-width) solid var(--current-color-border);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--current-color-tertiary);
    transition: all var(--transition-fast) var(--ease);
    font-size: var(--font-size-lg);
}

.wechat-modal-close:hover {
    background-color: var(--current-color-primary);
    color: var(--current-color-background);
    border-color: var(--current-color-primary);
}

.wechat-modal-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.wechat-modal-title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--current-color-primary);
}

.wechat-modal-subtitle {
    font-size: var(--font-size-sm);
    color: var(--current-color-tertiary);
}

.wechat-qr-container {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.wechat-qr-code {
    width: 220px;
    height: 220px;
    margin: 0 auto var(--spacing-md);
    padding: var(--spacing-md);
    background-color: white;
    border-radius: var(--border-radius-md);
    border: var(--border-width) solid var(--current-color-border);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    display: flex;
    align-items: center;
    justify-content: center;
}

.wechat-qr-placeholder {
    width: 180px;
    height: 180px;
    background: linear-gradient(45deg, var(--color-surface), var(--color-border));
    border-radius: var(--border-radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--current-color-tertiary);
    font-size: var(--font-size-sm);
    font-weight: 500;
}

.wechat-qr-tip {
    font-size: var(--font-size-xs);
    color: var(--current-color-tertiary);
    margin-top: var(--spacing-sm);
}

.wechat-info {
    text-align: center;
    padding: var(--spacing-lg);
    background-color: var(--current-color-surface);
    border-radius: var(--border-radius-md);
    margin-top: var(--spacing-xl);
}

.wechat-id {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--current-color-primary);
    margin-bottom: var(--spacing-xs);
    font-family: var(--font-mono), monospace;
    letter-spacing: 1px;
}

.wechat-instructions {
    font-size: var(--font-size-sm);
    color: var(--current-color-tertiary);
    line-height: var(--line-height-relaxed);
}


/* 响应式调整 */
@media (max-width: 768px) {
    .wechat-modal-content {
        padding: var(--spacing-xl);
        width: 95%;
    }
    
    .wechat-qr-code {
        width: 200px;
        height: 200px;
    }
    
    .wechat-qr-placeholder {
        width: 160px;
        height: 160px;
    }
}

@media (max-width: 480px) {
    .wechat-modal-content {
        padding: var(--spacing-lg);
    }
    
    .wechat-qr-code {
        width: 180px;
        height: 180px;
    }
    
    .wechat-qr-placeholder {
        width: 140px;
        height: 140px;
        font-size: var(--font-size-xs);
    }
}

/* 页脚 */
.footer {
    border-top: var(--border-width) solid var(--current-color-border);
    padding: var(--spacing-3xl) 0 var(--spacing-xl);
}

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

.footer-logo {
    font-weight: 700;
    font-size: var(--font-size-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

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

.footer-link {
    font-size: var(--font-size-sm);
    color: var(--current-color-tertiary);
    transition: color var(--transition-fast) var(--ease);
}

.footer-link:hover {
    color: var(--current-color-primary);
}

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-xl);
    border-top: var(--border-width) solid var(--current-color-border);
    color: var(--current-color-tertiary);
    font-size: var(--font-size-sm);
}

.footer-bottom p {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    gap: 5px;
}

#beian-mps {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    gap: 3px;
}

.footer-bottom a {
    color: inherit;
}

/* 响应式设计 */
@media (max-width: 1024px) {
    .grid-cols-4 {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .navbar-container {
        height: 70px;
    }

    .nav-links {
        display: none;
    }

    .mobile-menu-btn {
        display: flex;
    }

    .hero-title {
        font-size: var(--font-size-4xl);
    }

    .hero-subtitle {
        font-size: var(--font-size-xl);
    }

    .grid-cols-2,
    .grid-cols-3 {
        grid-template-columns: 1fr;
    }

    .section {
        padding: var(--spacing-3xl) 0;
    }

    .footer-content {
        flex-direction: column;
        text-align: center;
    }

    .footer-links {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-lg);
    }

    .hero-title {
        font-size: var(--font-size-3xl);
    }

    .hero-buttons {
        flex-direction: column;
        align-items: stretch;
    }

    .btn {
        justify-content: center;
    }

    .section {
        padding: var(--spacing-2xl) 0;
    }
}

/* 动画 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-fade-in-up {
    animation: fadeInUp var(--transition-slow) var(--ease) forwards;
}

/* 打印样式 */
@media print {

    .navbar,
    .theme-toggle,
    .mobile-menu-btn,
    .footer {
        display: none !important;
    }

    body {
        background: white;
        color: black;
    }

    .hero-section {
        min-height: auto;
        padding-top: 0;
    }

    .section {
        padding: 2rem 0;
        page-break-inside: avoid;
    }

    a {
        color: black;
        text-decoration: none;
    }

    a::after {
        display: none;
    }
}

/* 返回顶部按钮 */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background-color: var(--current-color-primary);
    color: var(--current-color-background);
    border: var(--border-width) solid var(--current-color-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all var(--transition-normal) var(--ease);
    z-index: 999;
    font-size: var(--font-size-lg);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background-color: var(--current-color-background);
    color: var(--current-color-primary);
    transform: translateY(-4px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
}

.back-to-top:active {
    transform: translateY(-2px);
}

/* 响应式调整 */
@media (max-width: 768px) {
    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 45px;
        height: 45px;
        font-size: var(--font-size-base);
    }
}

@media (max-width: 480px) {
    .back-to-top {
        bottom: 15px;
        right: 15px;
        width: 40px;
        height: 40px;
    }
}