/* 全局重置与基础 */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
    background: #f4f7fc;
    color: #1a2639;
    line-height: 1.6;
    transition: background 0.3s, color 0.3s;
    scroll-behavior: smooth;
}

body.dark {
    background: #0b1a2e;
    color: #e0e9f5;
}

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

/* 毛玻璃效果 */
.glass {
    background: rgba(255, 255, 255, 0.25);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 32px;
    box-shadow: 0 12px 30px rgba(0, 0, 0, 0.08);
}

.dark .glass {
    background: rgba(10, 25, 47, 0.4);
    border-color: rgba(100, 150, 255, 0.15);
}

/* 按钮 */
.btn {
    display: inline-block;
    padding: 12px 28px;
    border-radius: 40px;
    font-weight: 600;
    background: linear-gradient(135deg, #1e90ff, #0f5bb5);
    color: #fff;
    border: none;
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: 0 8px 20px rgba(30, 144, 255, 0.25);
    text-decoration: none;
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 12px 28px rgba(30, 144, 255, 0.4);
}

.dark .btn {
    background: linear-gradient(135deg, #3a9bff, #1a6bc4);
}

/* 导航 */
header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

.dark header {
    background: rgba(11, 26, 46, 0.8);
    border-bottom-color: #1f3a5f;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 0;
}

.logo {
    font-weight: 700;
    font-size: 1.6rem;
    background: linear-gradient(135deg, #1e90ff, #0f5bb5);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    gap: 28px;
    align-items: center;
}

.nav-links a {
    text-decoration: none;
    color: #1a2639;
    font-weight: 500;
    transition: color 0.2s;
}

.dark .nav-links a {
    color: #c8d8f0;
}

.nav-links a:hover {
    color: #1e90ff;
}

.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 6px;
}

.menu-toggle span {
    width: 28px;
    height: 3px;
    background: #1a2639;
    border-radius: 6px;
    transition: 0.2s;
}

.dark .menu-toggle span {
    background: #e0e9f5;
}

.theme-toggle {
    background: none;
    border: none;
    font-size: 1.4rem;
    cursor: pointer;
    padding: 4px 10px;
    border-radius: 30px;
}

/* 移动端菜单 */
.mobile-nav {
    display: none;
    flex-direction: column;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-radius: 24px;
    padding: 20px;
    position: absolute;
    top: 70px;
    left: 20px;
    right: 20px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
}

.dark .mobile-nav {
    background: rgba(11, 26, 46, 0.95);
}

.mobile-nav.open {
    display: flex;
}

.mobile-nav a {
    padding: 12px 0;
    border-bottom: 1px solid #e6edf5;
    text-decoration: none;
    color: #1a2639;
    font-weight: 500;
}

.dark .mobile-nav a {
    border-color: #1f3a5f;
    color: #c8d8f0;
}

/* Hero 轮播 */
.hero-banner {
    position: relative;
    overflow: hidden;
    border-radius: 36px;
    margin: 30px 0;
    background: #0b1a2e;
    min-height: 360px;
}

.hero-slide {
    display: none;
    padding: 60px 40px;
    color: #fff;
    background: linear-gradient(135deg, #0f2b4a, #1a4b7a);
}

.hero-slide.active {
    display: block;
    animation: fade 0.8s ease;
}

@keyframes fade {
    from {
        opacity: 0.3;
    }
    to {
        opacity: 1;
    }
}

.hero-slide h1 {
    font-size: 2.8rem;
    font-weight: 700;
    margin-bottom: 20px;
}

.hero-slide p {
    font-size: 1.2rem;
    max-width: 600px;
    margin-bottom: 28px;
}

.hero-indicators {
    position: absolute;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 12px;
}

.hero-indicators span {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.4);
    cursor: pointer;
    transition: background 0.3s;
}

.hero-indicators span.active {
    background: #fff;
}

/* 卡片布局 */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 24px;
    margin: 40px 0;
}

.card {
    background: #fff;
    border-radius: 28px;
    padding: 28px 22px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.04);
    transition: transform 0.2s, box-shadow 0.2s;
    border: 1px solid rgba(0, 0, 0, 0.02);
}

.dark .card {
    background: #142b44;
    border-color: #1f3a5f;
}

.card:hover {
    transform: translateY(-6px);
    box-shadow: 0 20px 35px rgba(0, 0, 0, 0.08);
}

.card h3 {
    font-size: 1.5rem;
    margin-bottom: 10px;
}

.card p {
    color: #3a4a62;
}

.dark .card p {
    color: #b0c8e5;
}

/* 数字动画 */
.stat-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-around;
    gap: 30px;
    margin: 50px 0;
}

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

.stat-number {
    font-size: 3rem;
    font-weight: 800;
    color: #1e90ff;
}

.dark .stat-number {
    color: #5aadff;
}

/* FAQ */
.faq-item {
    border-bottom: 1px solid #dce4ed;
    padding: 18px 0;
    cursor: pointer;
}

.dark .faq-item {
    border-color: #1f3a5f;
}

.faq-question {
    display: flex;
    justify-content: space-between;
    font-weight: 600;
    font-size: 1.1rem;
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease;
    color: #3a4a62;
}

.dark .faq-answer {
    color: #b0c8e5;
}

.faq-item.open .faq-answer {
    max-height: 200px;
    margin-top: 12px;
}

/* 返回顶部 */
#backTop {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: #1e90ff;
    color: #fff;
    border: none;
    font-size: 1.6rem;
    box-shadow: 0 8px 20px rgba(30, 144, 255, 0.3);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 99;
    cursor: pointer;
    transition: opacity 0.3s;
}

#backTop.show {
    display: flex;
}

/* 辅助 */
.section-title {
    font-size: 2rem;
    margin: 50px 0 20px;
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: #1e90ff;
    border-radius: 4px;
    margin-top: 8px;
}

.dark .section-title::after {
    background: #5aadff;
}

.footer {
    background: #0b1a2e;
    color: #b0c8e5;
    padding: 40px 0;
    margin-top: 60px;
    border-radius: 40px 40px 0 0;
}

.dark .footer {
    background: #05101f;
}

.footer a {
    color: #8ab8ff;
}

.grid-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
}

.search-box {
    display: flex;
    gap: 10px;
    margin: 20px 0;
}

.search-box input {
    flex: 1;
    padding: 14px 20px;
    border-radius: 60px;
    border: 1px solid #d4e0ec;
    background: #fff;
    font-size: 1rem;
    outline: none;
    transition: border-color 0.2s;
}

.search-box input:focus {
    border-color: #1e90ff;
}

.dark .search-box input {
    background: #142b44;
    border-color: #1f3a5f;
    color: #fff;
}

.dark .search-box input::placeholder {
    color: #8aa8c8;
}

.breadcrumb {
    padding: 10px 0;
    font-size: 0.9rem;
    color: #5a6f8a;
}

.breadcrumb span {
    color: #1e90ff;
}

/* 滚动动画 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.card,
.glass,
.stat-item,
.faq-item {
    animation: fadeInUp 0.6s ease forwards;
}

.card:nth-child(2),
.glass:nth-child(2),
.stat-item:nth-child(2) {
    animation-delay: 0.1s;
}

.card:nth-child(3),
.glass:nth-child(3),
.stat-item:nth-child(3) {
    animation-delay: 0.2s;
}

.card:nth-child(4),
.stat-item:nth-child(4) {
    animation-delay: 0.3s;
}

/* 响应式 */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .menu-toggle {
        display: flex;
    }

    .hero-slide h1 {
        font-size: 2rem;
    }

    .hero-slide p {
        font-size: 1rem;
    }

    .hero-slide {
        padding: 40px 20px;
    }

    .stat-grid {
        gap: 20px;
    }

    .stat-number {
        font-size: 2.2rem;
    }

    .section-title {
        font-size: 1.6rem;
    }

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

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

    .footer {
        text-align: center;
    }

    #backTop {
        bottom: 20px;
        right: 20px;
        width: 44px;
        height: 44px;
        font-size: 1.3rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 12px;
    }

    .hero-slide h1 {
        font-size: 1.6rem;
    }

    .hero-banner {
        min-height: 280px;
    }

    .btn {
        padding: 10px 20px;
        font-size: 0.9rem;
    }

    .logo {
        font-size: 1.3rem;
    }
}