/* 全局重置与变量 */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
:root {
    --primary: #ff6b35;
    --primary-dark: #e55a2b;
    --secondary: #1a1a2e;
    --accent: #16213e;
    --bg: #f4f7fc;
    --text: #2d3436;
    --text-light: #636e72;
    --white: #ffffff;
    --glass: rgba(255,255,255,0.85);
    --shadow: 0 8px 32px rgba(0,0,0,0.08);
    --radius: 20px;
    --radius-sm: 12px;
    --transition: 0.35s cubic-bezier(0.4, 0, 0.2, 1);
    --max-width: 1200px;
    --font: 'Segoe UI', system-ui, -apple-system, sans-serif;
}
.dark-mode {
    --bg: #0f0f1a;
    --text: #e4e6eb;
    --text-light: #b0b3b8;
    --glass: rgba(26,26,46,0.9);
    --shadow: 0 8px 32px rgba(0,0,0,0.4);
    --white: #1a1a2e;
}
html { scroll-behavior: smooth; font-size: 16px; }
body {
    font-family: var(--font);
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
    transition: background var(--transition), color var(--transition);
    overflow-x: hidden;
}
a { color: var(--primary); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--primary-dark); }
img, svg { max-width: 100%; height: auto; display: block; }
ul { list-style: none; }
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 24px; }
.section { padding: 80px 0; }
.section-title {
    font-size: 2.2rem;
    font-weight: 800;
    text-align: center;
    margin-bottom: 16px;
    background: linear-gradient(135deg, var(--primary), #f093fb);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.section-subtitle {
    text-align: center;
    color: var(--text-light);
    font-size: 1.1rem;
    max-width: 700px;
    margin: 0 auto 48px;
}
.btn {
    display: inline-block;
    padding: 14px 36px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #fff;
    border: none;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform var(--transition), box-shadow var(--transition);
    box-shadow: 0 4px 20px rgba(255,107,53,0.3);
}
.btn:hover { transform: translateY(-3px); box-shadow: 0 8px 30px rgba(255,107,53,0.4); }
.btn-outline {
    background: transparent;
    border: 2px solid var(--primary);
    color: var(--primary);
    box-shadow: none;
}
.btn-outline:hover { background: var(--primary); color: #fff; }
.glass-card {
    background: var(--glass);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 32px;
    transition: transform var(--transition), box-shadow var(--transition);
    border: 1px solid rgba(255,255,255,0.2);
}
.glass-card:hover { transform: translateY(-6px); box-shadow: 0 16px 48px rgba(0,0,0,0.12); }
.dark-mode .glass-card { border-color: rgba(255,255,255,0.05); }
/* 导航 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background: var(--glass);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(255,255,255,0.15);
    transition: background var(--transition), box-shadow var(--transition);
}
.navbar.scrolled { box-shadow: 0 4px 20px rgba(0,0,0,0.08); }
.navbar .container { display: flex; align-items: center; justify-content: space-between; height: 70px; }
.logo { font-size: 1.6rem; font-weight: 900; color: var(--primary); display: flex; align-items: center; gap: 10px; }
.logo svg { width: 36px; height: 36px; }
.nav-links { display: flex; gap: 28px; align-items: center; }
.nav-links a {
    color: var(--text);
    font-weight: 500;
    font-size: 0.95rem;
    position: relative;
    padding: 4px 0;
}
.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary);
    transition: width var(--transition);
}
.nav-links a:hover::after, .nav-links a.active::after { width: 100%; }
.nav-links a:hover { color: var(--primary); }
.dark-toggle {
    background: none;
    border: none;
    font-size: 1.4rem;
    cursor: pointer;
    color: var(--text);
    padding: 4px 8px;
    border-radius: 8px;
    transition: background var(--transition);
}
.dark-toggle:hover { background: rgba(255,107,53,0.1); }
.hamburger { display: none; flex-direction: column; gap: 5px; cursor: pointer; background: none; border: none; padding: 4px; }
.hamburger span { width: 26px; height: 3px; background: var(--text); border-radius: 4px; transition: var(--transition); }
@media (max-width: 900px) {
    .nav-links { 
        position: fixed; top: 70px; left: 0; width: 100%; 
        flex-direction: column; background: var(--glass); backdrop-filter: blur(20px);
        padding: 20px 0; gap: 16px; display: none; 
        border-bottom: 1px solid rgba(255,255,255,0.1);
    }
    .nav-links.open { display: flex; }
    .hamburger { display: flex; }
}
/* Hero */
.hero {
    padding: 140px 0 80px;
    background: linear-gradient(135deg, var(--secondary) 0%, var(--accent) 100%);
    color: #fff;
    position: relative;
    overflow: hidden;
}
.hero::before {
    content: '';
    position: absolute;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(255,107,53,0.15), transparent 70%);
    top: -200px;
    right: -200px;
    border-radius: 50%;
}
.hero .container { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: center; position: relative; z-index: 1; }
.hero h1 { font-size: 3.2rem; font-weight: 900; line-height: 1.2; margin-bottom: 20px; }
.hero h1 span { background: linear-gradient(135deg, var(--primary), #f093fb); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.hero p { font-size: 1.15rem; opacity: 0.85; margin-bottom: 32px; max-width: 500px; }
.hero-actions { display: flex; gap: 16px; flex-wrap: wrap; }
.hero-visual { display: flex; justify-content: center; align-items: center; }
.hero-visual svg { width: 100%; max-width: 480px; height: auto; filter: drop-shadow(0 20px 40px rgba(255,107,53,0.2)); }
@media (max-width: 768px) {
    .hero .container { grid-template-columns: 1fr; text-align: center; }
    .hero h1 { font-size: 2.2rem; }
    .hero p { margin: 0 auto 32px; }
    .hero-actions { justify-content: center; }
}
/* Banner轮播 */
.banner-carousel {
    position: relative;
    overflow: hidden;
    border-radius: var(--radius);
    margin: 40px 0;
    height: 400px;
}
.banner-slide {
    position: absolute;
    inset: 0;
    opacity: 0;
    transition: opacity 0.8s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 40px;
    border-radius: var(--radius);
}
.banner-slide.active { opacity: 1; }
.banner-slide:nth-child(1) { background: linear-gradient(135deg, #667eea, #764ba2); }
.banner-slide:nth-child(2) { background: linear-gradient(135deg, #f093fb, #f5576c); }
.banner-slide:nth-child(3) { background: linear-gradient(135deg, #4facfe, #00f2fe); }
.banner-content { text-align: center; color: #fff; }
.banner-content h3 { font-size: 2rem; margin-bottom: 12px; }
.banner-content p { font-size: 1.1rem; opacity: 0.9; max-width: 600px; }
.banner-dots { position: absolute; bottom: 20px; left: 50%; transform: translateX(-50%); display: flex; gap: 12px; }
.banner-dots span { width: 12px; height: 12px; border-radius: 50%; background: rgba(255,255,255,0.4); cursor: pointer; transition: var(--transition); }
.banner-dots span.active { background: #fff; transform: scale(1.2); }
@media (max-width: 600px) {
    .banner-carousel { height: 280px; }
    .banner-content h3 { font-size: 1.4rem; }
}
/* 网格 */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 32px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
@media (max-width: 900px) {
    .grid-3 { grid-template-columns: 1fr 1fr; }
    .grid-4 { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 600px) {
    .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
}
/* FAQ */
.faq-item { border-bottom: 1px solid rgba(0,0,0,0.06); padding: 18px 0; cursor: pointer; }
.dark-mode .faq-item { border-color: rgba(255,255,255,0.06); }
.faq-question { display: flex; justify-content: space-between; align-items: center; font-weight: 600; font-size: 1.05rem; }
.faq-question span { transition: transform var(--transition); }
.faq-item.open .faq-question span { transform: rotate(45deg); }
.faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.5s ease, padding 0.3s ease; color: var(--text-light); }
.faq-item.open .faq-answer { max-height: 300px; padding-top: 12px; }
/* 数字动画 */
.stat-number { font-size: 2.8rem; font-weight: 900; color: var(--primary); }
/* 页脚 */
footer {
    background: var(--secondary);
    color: rgba(255,255,255,0.8);
    padding: 60px 0 30px;
}
footer a { color: rgba(255,255,255,0.7); }
footer a:hover { color: var(--primary); }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 32px; margin-bottom: 40px; }
@media (max-width: 768px) {
    .footer-grid { grid-template-columns: 1fr 1fr; }
}
.footer-bottom { border-top: 1px solid rgba(255,255,255,0.1); padding-top: 24px; text-align: center; font-size: 0.9rem; }
/* 返回顶部 */
.back-top {
    position: fixed; bottom: 30px; right: 30px;
    width: 48px; height: 48px; border-radius: 50%;
    background: var(--primary); color: #fff;
    display: flex; align-items: center; justify-content: center;
    font-size: 1.4rem; cursor: pointer;
    opacity: 0; visibility: hidden;
    transition: var(--transition);
    border: none; z-index: 999;
    box-shadow: 0 4px 16px rgba(255,107,53,0.3);
}
.back-top.visible { opacity: 1; visibility: visible; }
/* 滚动动画 */
.fade-up { opacity: 0; transform: translateY(30px); transition: opacity 0.7s ease, transform 0.7s ease; }
.fade-up.visible { opacity: 1; transform: translateY(0); }
/* 搜索模拟 */
.search-box { display: flex; gap: 8px; max-width: 400px; margin: 0 auto 32px; }
.search-box input { flex: 1; padding: 12px 18px; border: 2px solid rgba(255,107,53,0.2); border-radius: 50px; background: var(--white); color: var(--text); font-size: 1rem; outline: none; transition: border var(--transition); }
.search-box input:focus { border-color: var(--primary); }
.search-box button { padding: 12px 24px; border-radius: 50px; }
/* 文章卡片 */
.article-card { display: flex; flex-direction: column; gap: 12px; }
.article-card svg { width: 100%; height: 180px; border-radius: var(--radius-sm); object-fit: cover; background: #e8ecf1; }
.dark-mode .article-card svg { background: #2a2a3e; }
.article-card h4 { font-size: 1.1rem; font-weight: 700; }
.article-card .date { font-size: 0.85rem; color: var(--text-light); }
/* 合作伙伴logo */
.partner-logos { display: flex; flex-wrap: wrap; gap: 24px; justify-content: center; align-items: center; }
.partner-logos svg { width: 100px; height: 50px; opacity: 0.6; transition: opacity var(--transition); }
.partner-logos svg:hover { opacity: 1; }