/* 全局重置与基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: #f5f7fa;
    color: #1a2a3a;
    line-height: 1.6;
    transition: background 0.3s, color 0.3s;
}

body.dark {
    background: #0d1b2a;
    color: #e0e6ed;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 头部导航 - 渐变背景 + 毛玻璃 */
header {
    background: linear-gradient(135deg, #1a3a5c, #2a5a8c);
    color: #fff;
    padding: 20px 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 20px rgba(0,0,0,0.15);
    backdrop-filter: blur(10px);
}

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

.logo {
    font-size: 1.8rem;
    font-weight: 700;
    letter-spacing: 1px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo svg {
    width: 40px;
    height: 40px;
}

nav ul {
    display: flex;
    list-style: none;
    gap: 25px;
    flex-wrap: wrap;
}

nav a {
    color: #fff;
    text-decoration: none;
    font-weight: 500;
    padding: 8px 0;
    border-bottom: 2px solid transparent;
    transition: 0.3s;
}

nav a:hover,
nav a.active {
    border-bottom-color: #ffd700;
}

.menu-toggle {
    display: none;
    background: none;
    border: 2px solid #fff;
    color: #fff;
    padding: 8px 16px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 1rem;
}

@media (max-width: 768px) {
    .menu-toggle {
        display: block;
    }
    nav ul {
        display: none;
        flex-direction: column;
        width: 100%;
        margin-top: 15px;
        gap: 10px;
    }
    nav ul.open {
        display: flex;
    }
}

/* Hero 区域 - 渐变 Banner + 毛玻璃卡片 + 动画 */
.hero {
    background: linear-gradient(135deg, #1a3a5c 0%, #2a5a8c 50%, #3a7ab5 100%);
    color: #fff;
    padding: 80px 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    animation: fadeInUp 1s;
}

.hero p {
    font-size: 1.3rem;
    max-width: 700px;
    margin: 0 auto 30px;
    opacity: 0.9;
}

.hero .btn {
    background: #ffd700;
    color: #1a3a5c;
    padding: 14px 40px;
    border-radius: 50px;
    font-weight: 700;
    text-decoration: none;
    display: inline-block;
    transition: 0.3s;
}

.hero .btn:hover {
    transform: scale(1.05);
    box-shadow: 0 10px 30px rgba(255,215,0,0.3);
}

.hero .carousel {
    margin-top: 40px;
    display: flex;
    gap: 20px;
    justify-content: center;
    flex-wrap: wrap;
}

.hero .carousel-item {
    background: rgba(255,255,255,0.1);
    backdrop-filter: blur(10px);
    padding: 30px;
    border-radius: 20px;
    width: 280px;
    border: 1px solid rgba(255,255,255,0.2);
    transition: 0.3s;
}

.hero .carousel-item:hover {
    transform: translateY(-10px);
    background: rgba(255,255,255,0.2);
}

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

/* 通用 Section 与标题 */
section {
    padding: 60px 0;
}

section h2 {
    font-size: 2.2rem;
    margin-bottom: 20px;
    position: relative;
    display: inline-block;
}

section h2::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: #ffd700;
    margin-top: 10px;
}

/* 卡片网格 - 圆角卡片 + hover 动画 */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 30px;
}

.card {
    background: #fff;
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.05);
    transition: 0.3s;
    border: 1px solid #eef2f7;
}

.dark .card {
    background: #1e2d3d;
    border-color: #2a3a4a;
}

.card:hover {
    transform: translateY(-8px);
    box-shadow: 0 15px 40px rgba(0,0,0,0.1);
}

.card h3 {
    font-size: 1.4rem;
    margin-bottom: 15px;
}

.card p {
    color: #5a6a7a;
}

.dark .card p {
    color: #b0c0d0;
}

.card svg {
    width: 60px;
    height: 60px;
    margin-bottom: 15px;
}

/* 统计数据 - 渐变背景 + 圆角 */
.stats {
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
    gap: 30px;
    background: linear-gradient(135deg, #1a3a5c, #2a5a8c);
    color: #fff;
    padding: 60px 20px;
    border-radius: 30px;
    margin: 40px 0;
}

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

.stat-number {
    font-size: 3rem;
    font-weight: 700;
}

.stat-label {
    font-size: 1.1rem;
    opacity: 0.8;
}

/* FAQ 组件 - 可展开 */
.faq-item {
    background: #fff;
    border-radius: 16px;
    margin-bottom: 15px;
    padding: 20px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.03);
    cursor: pointer;
    transition: 0.3s;
}

.dark .faq-item {
    background: #1e2d3d;
}

.faq-item h3 {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 1.2rem;
}

.faq-item .faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s;
}

.faq-item.open .faq-answer {
    max-height: 300px;
    margin-top: 15px;
}

.faq-item .icon {
    transition: 0.3s;
}

.faq-item.open .icon {
    transform: rotate(180deg);
}

/* 页脚 */
.footer {
    background: #0d1b2a;
    color: #b0c0d0;
    padding: 40px 0;
    margin-top: 60px;
}

.footer a {
    color: #b0c0d0;
    text-decoration: none;
}

.footer a:hover {
    color: #ffd700;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 30px;
}

/* 回到顶部按钮 */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: #1a3a5c;
    color: #fff;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    transition: 0.3s;
    border: none;
    font-size: 1.5rem;
}

.back-to-top.visible {
    opacity: 1;
}

/* 暗色模式切换按钮 */
.dark-mode-toggle {
    position: fixed;
    bottom: 30px;
    left: 30px;
    background: #1a3a5c;
    color: #fff;
    border: none;
    padding: 12px 20px;
    border-radius: 50px;
    cursor: pointer;
    font-weight: 600;
    transition: 0.3s;
    z-index: 200;
}

.dark-mode-toggle:hover {
    background: #2a5a8c;
}

/* 搜索框 */
.search-box {
    display: flex;
    gap: 10px;
    max-width: 400px;
    margin: 20px auto;
}

.search-box input {
    flex: 1;
    padding: 12px 20px;
    border: 2px solid #ddd;
    border-radius: 50px;
    font-size: 1rem;
    outline: none;
}

.search-box button {
    padding: 12px 25px;
    background: #1a3a5c;
    color: #fff;
    border: none;
    border-radius: 50px;
    cursor: pointer;
}

/* 面包屑导航 */
.breadcrumb {
    padding: 15px 0;
    font-size: 0.95rem;
    color: #5a6a7a;
}

.breadcrumb a {
    color: #1a3a5c;
    text-decoration: none;
}

.breadcrumb span {
    margin: 0 8px;
}

/* 响应式 - 手机适配 */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2rem;
    }
    .hero p {
        font-size: 1rem;
    }
    .stat-number {
        font-size: 2rem;
    }
}

/* 滚动入场动画 */
.animate-on-scroll {
    opacity: 0;
    transform: translateY(30px);
    transition: 0.6s;
}

.animate-on-scroll.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Banner 指示点 */
.banner-dots {
    display: flex;
    gap: 10px;
    justify-content: center;
    margin-top: 20px;
}

.banner-dots span {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: rgba(255,255,255,0.3);
    cursor: pointer;
    transition: 0.3s;
}

.banner-dots span.active {
    background: #ffd700;
}