/* 基础重置与暗黑模式变量 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
:root {
    --bg: #ffffff;
    --bg2: #f5f7fa;
    --text: #1a1a2e;
    --text2: #4a4a6a;
    --primary: #e94560;
    --primary-dark: #c73e54;
    --primary-light: #ff6b81;
    --accent: #0f3460;
    --glass: rgba(255,255,255,0.7);
    --shadow: 0 8px 32px rgba(0,0,0,0.08);
    --radius: 16px;
    --card-bg: #ffffff;
    --border: rgba(0,0,0,0.06);
    --nav-bg: rgba(255,255,255,0.85);
    --footer-bg: #0f3460;
    --footer-text: #ffffff;
    --gradient1: linear-gradient(135deg, #0f3460, #1a1a2e);
    --gradient2: linear-gradient(135deg, #e94560, #ff6b81);
    --gradient3: linear-gradient(135deg, #16213e, #0f3460);
}
body.dark {
    --bg: #0d0d1a;
    --bg2: #1a1a2e;
    --text: #e0e0e0;
    --text2: #a0a0c0;
    --glass: rgba(30,30,60,0.7);
    --shadow: 0 8px 32px rgba(0,0,0,0.3);
    --card-bg: #1a1a2e;
    --border: rgba(255,255,255,0.06);
    --nav-bg: rgba(13,13,26,0.9);
    --footer-bg: #0a0a14;
    --footer-text: #c0c0d0;
}
html {
    scroll-behavior: smooth;
}
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
    transition: background 0.3s, color 0.3s;
}
a {
    color: var(--primary);
    text-decoration: none;
}
img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* 导航 */
nav {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    background: var(--nav-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    padding: 0 20px;
    transition: background 0.3s;
}
.nav-inner {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}
.logo {
    font-size: 1.5rem;
    font-weight: 800;
    background: var(--gradient2);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    display: flex;
    align-items: center;
    gap: 8px;
}
.logo svg {
    width: 32px;
    height: 32px;
    -webkit-text-fill-color: initial;
}
.nav-links {
    display: flex;
    gap: 24px;
    list-style: none;
    align-items: center;
}
.nav-links a {
    color: var(--text);
    font-weight: 500;
    font-size: 0.95rem;
    transition: color 0.2s;
    position: relative;
}
.nav-links a:hover,
.nav-links a.active {
    color: var(--primary);
}
.nav-links a.active::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--primary);
    border-radius: 2px;
}
.dark-toggle {
    background: var(--glass);
    border: 1px solid var(--border);
    border-radius: 50%;
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 1.2rem;
    transition: 0.2s;
    color: var(--text);
}
.dark-toggle:hover {
    background: var(--primary);
    color: white;
}
.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.8rem;
    color: var(--text);
    cursor: pointer;
}
@media (max-width: 768px) {
    .nav-links {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 64px;
        left: 0;
        width: 100%;
        background: var(--nav-bg);
        backdrop-filter: blur(20px);
        padding: 20px;
        gap: 16px;
        border-bottom: 1px solid var(--border);
    }
    .nav-links.open {
        display: flex;
    }
    .mobile-menu-btn {
        display: block;
    }
}

/* 通用 */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}
section {
    padding: 80px 0;
}
.section-title {
    font-size: 2.2rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 16px;
    color: var(--text);
}
.section-sub {
    text-align: center;
    color: var(--text2);
    max-width: 700px;
    margin: 0 auto 48px;
    font-size: 1.1rem;
}
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}
.card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 28px 24px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
    transition: transform 0.3s, box-shadow 0.3s;
    backdrop-filter: blur(4px);
}
.card:hover {
    transform: translateY(-6px);
    box-shadow: 0 16px 48px rgba(0,0,0,0.12);
}
.card-icon {
    font-size: 2.5rem;
    margin-bottom: 16px;
    color: var(--primary);
}
.card h3 {
    font-size: 1.3rem;
    margin-bottom: 8px;
    font-weight: 600;
}
.card p {
    color: var(--text2);
    font-size: 0.95rem;
}

/* Hero Banner */
.hero {
    padding: 140px 0 80px;
    background: var(--gradient1);
    color: white;
    position: relative;
    overflow: hidden;
}
.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at 30% 40%, rgba(233,69,96,0.15), transparent 60%);
    animation: heroGlow 8s ease-in-out infinite alternate;
}
@keyframes heroGlow {
    0% { transform: translate(0,0); }
    100% { transform: translate(5%,5%); }
}
.hero-content {
    position: relative;
    z-index: 1;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 40px;
    flex-wrap: wrap;
}
.hero-text {
    flex: 1 1 500px;
}
.hero-text h1 {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 16px;
    line-height: 1.2;
}
.hero-text p {
    font-size: 1.2rem;
    opacity: 0.9;
    margin-bottom: 24px;
    max-width: 600px;
}
.hero-btns {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}
.btn {
    display: inline-block;
    padding: 14px 36px;
    border-radius: 50px;
    font-weight: 600;
    font-size: 1rem;
    transition: 0.3s;
    border: none;
    cursor: pointer;
    background: var(--gradient2);
    color: white;
    box-shadow: 0 4px 20px rgba(233,69,96,0.4);
}
.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(233,69,96,0.5);
}
.btn-outline {
    background: transparent;
    border: 2px solid rgba(255,255,255,0.5);
    box-shadow: none;
}
.btn-outline:hover {
    border-color: white;
    background: rgba(255,255,255,0.1);
}
.hero-visual {
    flex: 1 1 400px;
    display: flex;
    justify-content: center;
    position: relative;
}
.hero-visual svg {
    width: 100%;
    max-width: 450px;
    height: auto;
    filter: drop-shadow(0 20px 40px rgba(0,0,0,0.3));
}
@media (max-width: 768px) {
    .hero-text h1 { font-size: 2.2rem; }
    .hero { padding: 100px 0 60px; }
}

/* 轮播 */
.carousel {
    position: relative;
    overflow: hidden;
    border-radius: var(--radius);
    margin: 40px 0;
}
.carousel-track {
    display: flex;
    transition: transform 0.6s ease;
}
.carousel-slide {
    min-width: 100%;
    padding: 40px;
    background: var(--gradient3);
    color: white;
    text-align: center;
    border-radius: var(--radius);
}
.carousel-slide h3 {
    font-size: 1.8rem;
    margin-bottom: 12px;
}
.carousel-slide p {
    font-size: 1.1rem;
    opacity: 0.9;
    max-width: 600px;
    margin: 0 auto;
}
.carousel-nav {
    display: flex;
    justify-content: center;
    gap: 12px;
    margin-top: 16px;
}
.carousel-dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--border);
    cursor: pointer;
    transition: 0.3s;
    border: none;
}
.carousel-dot.active {
    background: var(--primary);
    transform: scale(1.2);
}

/* 数据展示 */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 24px;
    text-align: center;
}
.stat-item {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 32px 16px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
}
.stat-number {
    font-size: 2.8rem;
    font-weight: 800;
    color: var(--primary);
    display: block;
}
.stat-label {
    color: var(--text2);
    margin-top: 8px;
    font-size: 1rem;
}

/* FAQ */
.faq-item {
    background: var(--card-bg);
    border-radius: 12px;
    margin-bottom: 12px;
    border: 1px solid var(--border);
    overflow: hidden;
    transition: 0.2s;
}
.faq-question {
    padding: 18px 24px;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 1.05rem;
    color: var(--text);
    background: none;
    border: none;
    width: 100%;
    text-align: left;
}
.faq-question::after {
    content: '+';
    font-size: 1.5rem;
    transition: 0.3s;
    color: var(--primary);
}
.faq-item.open .faq-question::after {
    content: '−';
}
.faq-answer {
    padding: 0 24px 18px;
    color: var(--text2);
    display: none;
    line-height: 1.6;
}
.faq-item.open .faq-answer {
    display: block;
}

/* Footer */
footer {
    background: var(--footer-bg);
    color: var(--footer-text);
    padding: 60px 0 30px;
}
.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 32px;
    margin-bottom: 32px;
}
.footer-col h4 {
    font-size: 1.1rem;
    margin-bottom: 16px;
    font-weight: 600;
    color: white;
}
.footer-col p, .footer-col a {
    color: rgba(255,255,255,0.7);
    font-size: 0.9rem;
    line-height: 2;
    display: block;
}
.footer-col a:hover {
    color: var(--primary-light);
}
.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.1);
    padding-top: 24px;
    text-align: center;
    font-size: 0.85rem;
    color: rgba(255,255,255,0.5);
}

/* 滚动动画 */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.7s ease, transform 0.7s ease;
}
.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* 搜索 */
.search-box {
    max-width: 400px;
    margin: 0 auto 40px;
    display: flex;
    gap: 8px;
}
.search-box input {
    flex: 1;
    padding: 12px 20px;
    border-radius: 50px;
    border: 1px solid var(--border);
    background: var(--card-bg);
    color: var(--text);
    font-size: 1rem;
    outline: none;
}
.search-box input:focus {
    border-color: var(--primary);
}
.search-box button {
    padding: 12px 24px;
    border-radius: 50px;
    border: none;
    background: var(--primary);
    color: white;
    font-weight: 600;
    cursor: pointer;
}

/* 返回顶部 */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--primary);
    color: white;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    box-shadow: 0 4px 20px rgba(233,69,96,0.4);
    opacity: 0;
    transform: translateY(20px);
    transition: 0.3s;
    z-index: 999;
}
.back-to-top.show {
    opacity: 1;
    transform: translateY(0);
}

/* 响应式微调 */
@media (max-width: 480px) {
    .section-title { font-size: 1.8rem; }
    .hero-text h1 { font-size: 1.8rem; }
}

/* 滚动条美化 */
::-webkit-scrollbar {
    width: 8px;
}
::-webkit-scrollbar-track {
    background: var(--bg2);
}
::-webkit-scrollbar-thumb {
    background: var(--primary);
    border-radius: 4px;
}