/* ========================================
   广东理工学院后勤处 - 样式表
   ======================================== */

/* CSS变量定义 */
:root {
    /* 颜色系统 */
    --primary: #0055A4;
    --primary-dark: #003d7a;
    --primary-light: #e6f0fa;
    --accent: #f59e0b;
    --accent-light: #fef3c7;
    
    /* 背景色 */
    --bg-white: #ffffff;
    --bg-light: #f8fafc;
    --bg-gray: #f1f5f9;
    
    /* 文字颜色 */
    --text-dark: #1e293b;
    --text-body: #334155;
    --text-light: #64748b;
    --text-muted: #94a3b8;
    
    /* 边框 */
    --border-color: #e2e8f0;
    --border-light: #f1f5f9;
    
    /* 阴影 */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
    
    /* 圆角 */
    --radius-sm: 4px;
    --radius: 8px;
    --radius-lg: 12px;
    
    /* 间距 */
    --space-xs: 4px;
    --space-sm: 8px;
    --space: 16px;
    --space-md: 24px;
    --space-lg: 32px;
    --space-xl: 48px;
    --space-2xl: 64px;
    
    /* 过渡 */
    --transition: 0.3s ease;
    
    /* 布局 */
    --max-width: 1400px;
    --header-height: 70px;
    --nav-height: 50px;
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    color: var(--text-body);
    background-color: var(--bg-light);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: inherit;
    text-decoration: none;
    transition: color var(--transition);
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

ul, ol {
    list-style: none;
}

/* 容器 */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--space-md);
}

/* ========================================
   顶部栏
   ======================================== */
.top-bar {
    background: var(--bg-white);
    border-bottom: 1px solid var(--border-color);
    padding: var(--space-sm) 0;
    font-size: 14px;
}

.top-bar-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.current-date {
    color: var(--text-light);
}

.top-links {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.top-link {
    color: var(--text-light);
    transition: color var(--transition);
}

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

.divider {
    color: var(--border-color);
}

/* ========================================
   头部
   ======================================== */
.header {
    background: var(--bg-white);
    padding: var(--space-md) 0;
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    transition: box-shadow var(--transition);
}

.header.scrolled {
    box-shadow: var(--shadow-md);
}

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

.logo {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.logo-icon {
    width: 50px;
    height: 50px;
}

.logo-text h1 {
    font-size: 22px;
    font-weight: 700;
    color: var(--primary);
    line-height: 1.2;
}

.logo-text p {
    font-size: 14px;
    color: var(--text-light);
    margin-top: 2px;
}

.header-right {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.search-box {
    display: flex;
    align-items: center;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    overflow: hidden;
    transition: border-color var(--transition);
}

.search-box:focus-within {
    border-color: var(--primary);
}

.search-input {
    width: 200px;
    padding: var(--space-sm) var(--space);
    border: none;
    outline: none;
    font-size: 14px;
}

.search-btn {
    padding: var(--space-sm) var(--space);
    background: var(--primary);
    color: var(--bg-white);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background var(--transition);
}

.search-btn:hover {
    background: var(--primary-dark);
}

/* ========================================
   主导航
   ======================================== */
.main-nav {
    background: var(--primary);
    position: sticky;
    top: var(--header-height);
    z-index: 99;
}

.main-nav .container {
    position: relative;
}

.nav-list {
    display: flex;
    justify-content: center;
}

.nav-item {
    position: relative;
}

.nav-link {
    display: block;
    padding: 14px 20px;
    color: var(--bg-white);
    font-size: 15px;
    font-weight: 500;
    transition: background var(--transition);
    white-space: nowrap;
}

.nav-link:hover,
.nav-item.active .nav-link {
    background: rgba(255, 255, 255, 0.1);
}

.nav-item.active .nav-link {
    background: rgba(255, 255, 255, 0.15);
}

/* 子菜单 */
.submenu {
    position: absolute;
    top: 100%;
    left: 0;
    min-width: 160px;
    background: var(--bg-white);
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all var(--transition);
    z-index: 100;
}

.nav-item:hover .submenu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.submenu-link {
    display: block;
    padding: 12px 20px;
    color: var(--text-body);
    font-size: 14px;
    border-bottom: 1px solid var(--border-light);
    transition: all var(--transition);
}

.submenu-link:last-child {
    border-bottom: none;
}

.submenu-link:hover {
    background: var(--primary-light);
    color: var(--primary);
}

/* 移动端菜单按钮 */
.mobile-menu-btn {
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 44px;
    height: var(--nav-height);
    gap: 5px;
    cursor: pointer;
}

.mobile-menu-btn span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--bg-white);
    transition: all var(--transition);
}

/* ========================================
   Banner轮播
   ======================================== */
.banner {
    position: relative;
    height: 480px;
    overflow: hidden;
}

.banner-slider {
    height: 100%;
    position: relative;
}

.banner-slide {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity 0.5s ease;
}

.banner-slide.active {
    opacity: 1;
}

.banner-content {
    text-align: center;
    color: var(--bg-white);
    padding: var(--space-xl);
}

.banner-content h2 {
    font-size: 48px;
    font-weight: 700;
    margin-bottom: var(--space-md);
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

.banner-content p {
    font-size: 20px;
    opacity: 0.9;
}

.banner-controls {
    position: absolute;
    top: 50%;
    left: 0;
    right: 0;
    transform: translateY(-50%);
    display: flex;
    justify-content: space-between;
    padding: 0 var(--space-md);
}

.banner-prev,
.banner-next {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    color: var(--bg-white);
    display: flex;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(4px);
    transition: all var(--transition);
}

.banner-prev:hover,
.banner-next:hover {
    background: rgba(255, 255, 255, 0.4);
}

.banner-dots {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: var(--space-sm);
}

.dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.5);
    cursor: pointer;
    transition: all var(--transition);
}

.dot.active {
    background: var(--bg-white);
    transform: scale(1.2);
}

/* ========================================
   区块通用样式
   ======================================== */
section {
    padding: var(--space-2xl) 0;
}

.section-header {
    text-align: center;
    margin-bottom: var(--space-xl);
}

.section-title {
    font-size: 32px;
    font-weight: 700;
    color: var(--text-dark);
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: var(--primary);
    border-radius: 2px;
}

.section-subtitle {
    margin-top: var(--space-md);
    color: var(--text-light);
    font-size: 16px;
}

/* ========================================
   快捷服务
   ======================================== */
.quick-services {
    background: var(--bg-white);
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: var(--space-md);
}

.service-card {
    background: var(--bg-light);
    padding: var(--space-lg);
    border-radius: var(--radius-lg);
    text-align: center;
    transition: all var(--transition);
    border: 1px solid transparent;
}

.service-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary);
    background: var(--bg-white);
}

.service-icon {
    width: 70px;
    height: 70px;
    margin: 0 auto var(--space-md);
    background: var(--primary-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary);
    transition: all var(--transition);
}

.service-card:hover .service-icon {
    background: var(--primary);
    color: var(--bg-white);
}

.service-card h3 {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: var(--space-xs);
}

.service-card p {
    font-size: 13px;
    color: var(--text-light);
}

/* ========================================
   新闻动态
   ======================================== */
.news-section {
    background: var(--bg-light);
}

.news-wrapper {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: var(--space-lg);
}

.news-column {
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow);
}

.column-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-md) var(--space-lg);
    border-bottom: 2px solid var(--primary);
}

.column-title {
    font-size: 20px;
    font-weight: 600;
    color: var(--primary);
}

.more-link {
    display: flex;
    align-items: center;
    gap: 4px;
    color: var(--text-light);
    font-size: 14px;
    transition: color var(--transition);
}

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

/* 通知列表 */
.notice-list {
    padding: var(--space-md);
}

.notice-item {
    display: flex;
    align-items: center;
    padding: var(--space-md);
    border-bottom: 1px solid var(--border-light);
    transition: background var(--transition);
    gap: var(--space-sm);
}

.notice-item:last-child {
    border-bottom: none;
}

.notice-item:hover {
    background: var(--bg-light);
}

.notice-tag {
    padding: 2px 8px;
    font-size: 12px;
    border-radius: var(--radius-sm);
    background: var(--primary-light);
    color: var(--primary);
    white-space: nowrap;
}

.notice-tag.important {
    background: #fef2f2;
    color: #dc2626;
}

.notice-title {
    flex: 1;
    font-size: 14px;
    color: var(--text-body);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.notice-date {
    font-size: 13px;
    color: var(--text-muted);
    white-space: nowrap;
}

/* 新闻列表 */
.news-items {
    padding: var(--space-md);
}

.news-item {
    display: flex;
    gap: var(--space-md);
    padding: var(--space-md);
    border-bottom: 1px solid var(--border-light);
    transition: background var(--transition);
}

.news-item:last-child {
    border-bottom: none;
}

.news-item:hover {
    background: var(--bg-light);
}

.news-image {
    width: 180px;
    height: 120px;
    flex-shrink: 0;
    border-radius: var(--radius);
    overflow: hidden;
}

.news-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition);
}

.news-item:hover .news-image img {
    transform: scale(1.05);
}

.news-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.news-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: var(--space-sm);
    transition: color var(--transition);
}

.news-item:hover .news-title {
    color: var(--primary);
}

.news-summary {
    font-size: 14px;
    color: var(--text-light);
    line-height: 1.6;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.news-meta {
    display: flex;
    gap: var(--space-md);
    font-size: 13px;
    color: var(--text-muted);
    margin-top: auto;
}

/* ========================================
   部门概况
   ======================================== */
.about-section {
    background: var(--bg-white);
}

.about-content {
    max-width: 1000px;
    margin: 0 auto;
}

.about-intro {
    text-align: center;
    padding: var(--space-lg);
    background: var(--primary-light);
    border-radius: var(--radius-lg);
    margin-bottom: var(--space-xl);
}

.about-intro p {
    font-size: 16px;
    line-height: 1.8;
    color: var(--text-body);
}

.about-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-lg);
    margin-bottom: var(--space-xl);
}

.stat-item {
    text-align: center;
    padding: var(--space-lg);
    background: var(--bg-light);
    border-radius: var(--radius-lg);
}

.stat-number {
    display: block;
    font-size: 42px;
    font-weight: 700;
    color: var(--primary);
    line-height: 1;
}

.stat-label {
    display: block;
    margin-top: var(--space-sm);
    font-size: 14px;
    color: var(--text-light);
}

.about-features {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-lg);
}

.feature-item {
    text-align: center;
    padding: var(--space-xl);
    background: var(--bg-light);
    border-radius: var(--radius-lg);
    transition: all var(--transition);
}

.feature-item:hover {
    background: var(--primary);
    transform: translateY(-5px);
}

.feature-item:hover .feature-icon,
.feature-item:hover h4,
.feature-item:hover p {
    color: var(--bg-white);
}

.feature-icon {
    width: 60px;
    height: 60px;
    margin: 0 auto var(--space-md);
    color: var(--primary);
}

.feature-item h4 {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: var(--space-sm);
}

.feature-item p {
    font-size: 14px;
    color: var(--text-light);
}

/* ========================================
   服务指南
   ======================================== */
.services-detail {
    background: var(--bg-light);
}

.services-tabs {
    display: flex;
    justify-content: center;
    gap: var(--space-md);
    margin-bottom: var(--space-xl);
    flex-wrap: wrap;
}

.service-tab {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-lg);
    background: var(--bg-white);
    border-radius: var(--radius);
    font-size: 15px;
    font-weight: 500;
    color: var(--text-body);
    transition: all var(--transition);
    box-shadow: var(--shadow-sm);
}

.service-tab:hover {
    background: var(--primary-light);
    color: var(--primary);
}

.service-tab.active {
    background: var(--primary);
    color: var(--bg-white);
}

.service-tab svg {
    flex-shrink: 0;
}

.service-panels {
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
}

.service-panel {
    display: none;
    padding: var(--space-xl);
}

.service-panel.active {
    display: block;
}

.panel-content h3 {
    font-size: 24px;
    font-weight: 600;
    color: var(--primary);
    margin-bottom: var(--space-md);
    text-align: center;
}

.panel-content > p {
    text-align: center;
    color: var(--text-light);
    margin-bottom: var(--space-xl);
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.service-info-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-lg);
    margin-bottom: var(--space-xl);
}

.info-card {
    background: var(--bg-light);
    padding: var(--space-lg);
    border-radius: var(--radius);
    text-align: center;
}

.info-card h4 {
    font-size: 16px;
    font-weight: 600;
    color: var(--primary);
    margin-bottom: var(--space-md);
    padding-bottom: var(--space-sm);
    border-bottom: 2px solid var(--primary);
    display: inline-block;
}

.info-card p {
    font-size: 14px;
    color: var(--text-body);
    margin-bottom: var(--space-xs);
}

/* ========================================
   规章制度
   ======================================== */
.regulations-section {
    background: var(--bg-white);
}

.regulations-tabs {
    display: flex;
    justify-content: center;
    gap: var(--space-md);
    margin-bottom: var(--space-xl);
}

.reg-tab {
    padding: var(--space-md) var(--space-xl);
    background: var(--bg-light);
    border-radius: var(--radius);
    font-size: 15px;
    font-weight: 500;
    color: var(--text-body);
    transition: all var(--transition);
}

.reg-tab:hover {
    background: var(--primary-light);
    color: var(--primary);
}

.reg-tab.active {
    background: var(--primary);
    color: var(--bg-white);
}

.reg-panels {
    max-width: 900px;
    margin: 0 auto;
}

.reg-panel {
    display: none;
}

.reg-panel.active {
    display: block;
}

.regulation-list {
    background: var(--bg-light);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.regulation-item {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-md) var(--space-lg);
    border-bottom: 1px solid var(--border-color);
    transition: background var(--transition);
}

.regulation-item:last-child {
    border-bottom: none;
}

.regulation-item:hover {
    background: var(--bg-white);
}

.reg-icon {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary-light);
    color: var(--primary);
    border-radius: var(--radius);
    flex-shrink: 0;
}

.reg-title {
    flex: 1;
    font-size: 15px;
    color: var(--text-body);
}

.regulation-item:hover .reg-title {
    color: var(--primary);
}

.reg-date {
    font-size: 13px;
    color: var(--text-muted);
}

/* ========================================
   下载中心
   ======================================== */
.download-section {
    background: var(--bg-light);
}

.download-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-md);
}

.download-card {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-lg);
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    transition: all var(--transition);
}

.download-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

.download-icon {
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary-light);
    color: var(--primary);
    border-radius: var(--radius);
    flex-shrink: 0;
}

.download-info {
    flex: 1;
}

.download-info h4 {
    font-size: 15px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 4px;
}

.download-format {
    font-size: 12px;
    color: var(--text-muted);
}

.download-btn {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary);
    color: var(--bg-white);
    border-radius: 50%;
    transition: all var(--transition);
}

.download-card:hover .download-btn {
    background: var(--primary-dark);
    transform: scale(1.1);
}

/* ========================================
   联系我们
   ======================================== */
.contact-section {
    background: var(--bg-white);
}

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

.contact-info {
    padding: var(--space-xl);
    background: var(--primary);
    border-radius: var(--radius-lg);
    color: var(--bg-white);
}

.contact-item {
    display: flex;
    gap: var(--space-md);
    padding: var(--space-lg) 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
}

.contact-item:last-child {
    border-bottom: none;
}

.contact-icon {
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.15);
    border-radius: var(--radius);
    flex-shrink: 0;
}

.contact-text h4 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: var(--space-xs);
}

.contact-text p {
    font-size: 14px;
    opacity: 0.9;
    margin-bottom: 4px;
}

/* 联系表单 */
.contact-form {
    padding: var(--space-xl);
    background: var(--bg-light);
    border-radius: var(--radius-lg);
}

.contact-form h3 {
    font-size: 20px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: var(--space-lg);
    padding-bottom: var(--space-md);
    border-bottom: 2px solid var(--primary);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-md);
}

.form-group {
    margin-bottom: var(--space-md);
}

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-body);
    margin-bottom: var(--space-xs);
}

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

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

/* 按钮 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-md) var(--space-xl);
    border-radius: var(--radius);
    font-size: 15px;
    font-weight: 500;
    transition: all var(--transition);
}

.btn-primary {
    background: var(--primary);
    color: var(--bg-white);
}

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

.btn-block {
    width: 100%;
}

/* ========================================
   底部信息栏
   ======================================== */
.footer {
    background: var(--primary-dark);
    color: var(--bg-white);
    padding: var(--space-2xl) 0 0;
}

.footer-main {
    display: flex;
    gap: var(--space-2xl);
    padding-bottom: var(--space-xl);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    flex-shrink: 0;
}

.footer-logo {
    width: 60px;
    height: 60px;
}

.footer-brand-text h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: var(--space-xs);
}

.footer-brand-text p {
    font-size: 12px;
    opacity: 0.7;
}

.footer-links {
    flex: 1;
    display: flex;
    gap: var(--space-2xl);
}

.footer-column h4 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: var(--space-md);
}

.footer-column a {
    display: block;
    font-size: 14px;
    opacity: 0.8;
    margin-bottom: var(--space-sm);
    transition: all var(--transition);
}

.footer-column a:hover {
    opacity: 1;
    padding-left: var(--space-xs);
}

.footer-column p {
    font-size: 14px;
    opacity: 0.8;
    margin-bottom: var(--space-xs);
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    padding: var(--space-md) 0;
    font-size: 13px;
    opacity: 0.7;
}

/* ========================================
   返回顶部按钮
   ======================================== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--primary);
    color: var(--bg-white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all var(--transition);
    z-index: 1000;
}

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

.back-to-top:hover {
    background: var(--primary-dark);
    transform: translateY(-3px);
}

/* ========================================
   响应式设计
   ======================================== */

/* 平板端 */
@media (max-width: 1024px) {
    :root {
        --header-height: 60px;
        --nav-height: 45px;
    }

    .banner {
        height: 400px;
    }

    .banner-content h2 {
        font-size: 36px;
    }

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

    .news-wrapper {
        grid-template-columns: 1fr;
    }

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

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

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

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

    .contact-wrapper {
        grid-template-columns: 1fr;
    }

    .footer-main {
        flex-direction: column;
        gap: var(--space-xl);
    }

    .footer-links {
        flex-wrap: wrap;
        gap: var(--space-lg);
    }
}

/* 手机端 */
@media (max-width: 768px) {
    .container {
        padding: 0 var(--space);
    }

    section {
        padding: var(--space-xl) 0;
    }

    .top-bar {
        display: none;
    }

    .header {
        padding: var(--space-sm) 0;
    }

    .logo-icon {
        width: 40px;
        height: 40px;
    }

    .logo-text h1 {
        font-size: 18px;
    }

    .logo-text p {
        font-size: 12px;
    }

    .header-right {
        display: none;
    }

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

    .main-nav {
        position: fixed;
        top: 0;
        left: -100%;
        width: 280px;
        height: 100vh;
        z-index: 1000;
        transition: left var(--transition);
    }

    .main-nav.open {
        left: 0;
    }

    .main-nav .container {
        height: 100%;
        padding: 0;
    }

    .nav-list {
        flex-direction: column;
        height: 100%;
        padding-top: var(--space-xl);
        background: var(--primary);
    }

    .nav-item {
        border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    }

    .nav-link {
        padding: var(--space-md) var(--space-lg);
    }

    .submenu {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        background: rgba(0, 0, 0, 0.2);
    }

    .submenu-link {
        color: rgba(255, 255, 255, 0.8);
        padding: var(--space-sm) var(--space-lg) var(--space-sm) var(--space-xl);
    }

    .banner {
        height: 280px;
    }

    .banner-content h2 {
        font-size: 24px;
    }

    .banner-content p {
        font-size: 14px;
    }

    .banner-controls {
        display: none;
    }

    .section-title {
        font-size: 24px;
    }

    .services-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--space-sm);
    }

    .service-card {
        padding: var(--space-md);
    }

    .service-icon {
        width: 50px;
        height: 50px;
    }

    .service-icon svg {
        width: 28px;
        height: 28px;
    }

    .service-card h3 {
        font-size: 14px;
    }

    .service-card p {
        font-size: 12px;
    }

    .news-image {
        width: 100px;
        height: 80px;
    }

    .news-title {
        font-size: 14px;
    }

    .news-summary {
        font-size: 13px;
        -webkit-line-clamp: 1;
    }

    .about-stats {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--space-md);
    }

    .stat-number {
        font-size: 32px;
    }

    .about-features {
        grid-template-columns: 1fr;
    }

    .services-tabs {
        gap: var(--space-sm);
    }

    .service-tab {
        padding: var(--space-sm) var(--space-md);
        font-size: 14px;
    }

    .service-tab svg {
        width: 20px;
        height: 20px;
    }

    .service-panel {
        padding: var(--space-lg);
    }

    .panel-content h3 {
        font-size: 20px;
    }

    .service-info-grid {
        grid-template-columns: 1fr;
    }

    .regulations-tabs {
        gap: var(--space-sm);
    }

    .reg-tab {
        padding: var(--space-sm) var(--space-md);
        font-size: 14px;
    }

    .regulation-item {
        flex-wrap: wrap;
        gap: var(--space-sm);
    }

    .reg-title {
        width: 100%;
        order: 2;
    }

    .reg-date {
        order: 3;
    }

    .download-grid {
        grid-template-columns: 1fr;
    }

    .contact-info {
        padding: var(--space-lg);
    }

    .contact-item {
        padding: var(--space-md) 0;
    }

    .contact-icon {
        width: 40px;
        height: 40px;
    }

    .contact-form {
        padding: var(--space-lg);
    }

    .form-row {
        grid-template-columns: 1fr;
    }

    .footer-links {
        flex-direction: column;
        gap: var(--space-lg);
    }

    .footer-bottom {
        flex-direction: column;
        gap: var(--space-xs);
        text-align: center;
    }

    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 44px;
        height: 44px;
    }
}

/* 超小屏幕 */
@media (max-width: 480px) {
    .services-grid {
        grid-template-columns: 1fr;
    }

    .about-stats {
        grid-template-columns: 1fr 1fr;
    }

    .stat-item {
        padding: var(--space-md);
    }

    .stat-number {
        font-size: 28px;
    }

    .services-tabs {
        flex-direction: column;
    }

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

/* 打印样式 */
@media print {
    .top-bar,
    .main-nav,
    .banner-controls,
    .banner-dots,
    .back-to-top {
        display: none !important;
    }
}