/* 全局重置与变量 — 现代企业风格 */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
:root {
    --brand-primary: #0b1a2f;
    --brand-accent: #f0c674;
    --brand-accent2: #d4a54a;
    --glass-bg: rgba(255,255,255,0.08);
    --glass-border: rgba(255,255,255,0.15);
    --shadow-sm: 0 8px 20px rgba(0,0,0,0.2);
    --shadow-hover: 0 20px 40px rgba(0,0,0,0.3);
    --radius-card: 24px;
    --radius-btn: 40px;
    --transition: 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    --font-family: system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    --bg-body: #f5f7fc;
    --text-color: #1f2937;
    --card-bg: #ffffff;
    --footer-bg: #0b1a2f;
}
body.dark-mode {
    --bg-body: #0f172a;
    --text-color: #e2e8f0;
    --card-bg: #1e293b;
    --footer-bg: #020617;
    --glass-bg: rgba(0,0,0,0.2);
}
html { scroll-behavior: smooth; }
body {
    font-family: var(--font-family);
    background: var(--bg-body);
    color: var(--text-color);
    line-height: 1.6;
    transition: background 0.2s, color 0.2s;
}
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
img, svg { display: block; max-width: 100%; height: auto; }
.container { max-width: 1280px; margin: 0 auto; padding: 0 24px; }
/* 玻璃效果卡片 */
.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-card);
    box-shadow: var(--shadow-sm);
    transition: transform 0.2s, box-shadow 0.2s;
}
.glass-card:hover { box-shadow: var(--shadow-hover); transform: translateY(-4px); }
/* 圆角与阴影 */
.btn {
    display: inline-block;
    background: var(--brand-accent);
    color: #0b1a2f;
    font-weight: 600;
    padding: 12px 32px;
    border-radius: var(--radius-btn);
    box-shadow: 0 4px 14px rgba(240,198,116,0.3);
    transition: var(--transition);
    border: none;
    cursor: pointer;
}
.btn:hover { background: #e5b95a; transform: scale(1.02); }
/* 渐变banner */
.hero-gradient {
    background: linear-gradient(135deg, #0b1a2f 0%, #1f3a5f 70%, #2a4a7a 100%);
}
/* 导航吸顶+暗黑 */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(11,26,47,0.85);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid rgba(255,255,255,0.1);
}
.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 0;
}
.logo svg { width: 140px; height: 40px; }
.nav-list { display: flex; gap: 28px; font-weight: 500; }
.nav-list a { color: #f0f4fa; transition: color 0.2s; }
.nav-list a:hover, .nav-list a.active { color: var(--brand-accent); }
.dark-toggle { background: none; border: 1px solid rgba(255,255,255,0.2); color: #fff; border-radius: 30px; padding: 6px 16px; cursor: pointer; }
.mobile-menu-btn { display: none; background: none; border: none; color: #fff; font-size: 28px; }
/* 移动菜单 */
.mobile-nav { display: none; background: #0b1a2f; padding: 20px; border-radius: 20px; position: absolute; top: 70px; left: 20px; right: 20px; }
.mobile-nav.open { display: block; }
.mobile-nav a { display: block; padding: 12px 0; border-bottom: 1px solid rgba(255,255,255,0.1); color: #fff; }
/* 轮播 */
.carousel { position: relative; overflow: hidden; border-radius: 28px; }
.carousel-track { display: flex; transition: transform 0.5s ease; }
.carousel-slide { min-width: 100%; padding: 60px 40px; }
.carousel-btn { position: absolute; top: 50%; transform: translateY(-50%); background: rgba(255,255,255,0.2); border: none; color: #fff; font-size: 32px; padding: 8px 16px; border-radius: 40px; cursor: pointer; backdrop-filter: blur(4px); }
.carousel-btn.prev { left: 16px; }
.carousel-btn.next { right: 16px; }
/* 数字动画 */
.stat-number { font-size: 2.8rem; font-weight: 700; color: var(--brand-accent); }
/* 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); }
/* 卡片布局 */
.grid-3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 32px; }
.grid-2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 32px; }
.card { background: var(--card-bg); border-radius: var(--radius-card); padding: 28px; box-shadow: 0 4px 12px rgba(0,0,0,0.04); transition: var(--transition); }
.card:hover { box-shadow: 0 16px 32px rgba(0,0,0,0.08); }
.section-title { font-size: 2rem; font-weight: 700; margin-bottom: 40px; position: relative; display: inline-block; }
.section-title::after { content: ''; display: block; width: 60px; height: 4px; background: var(--brand-accent); margin-top: 8px; border-radius: 4px; }
.footer { background: var(--footer-bg); color: #cbd5e1; padding: 48px 0 24px; margin-top: 60px; }
.footer a { color: #cbd5e1; }
.footer-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px,1fr)); gap: 32px; }
/* 响应式 */
@media (max-width: 768px) {
    .nav-list { display: none; }
    .mobile-menu-btn { display: block; }
    .header-inner { padding: 8px 0; }
    .hero-gradient { padding: 40px 0 !important; }
    .carousel-slide { padding: 40px 20px; }
}
@media (max-width: 480px) {
    .stat-number { font-size: 2rem; }
}
/* 暗黑模式微调 */
body.dark-mode .card { background: #1e293b; }
body.dark-mode .glass-card { background: rgba(255,255,255,0.05); }
.back-to-top { position: fixed; bottom: 30px; right: 30px; background: var(--brand-accent); color: #0b1a2f; border: none; border-radius: 50%; width: 48px; height: 48px; font-size: 24px; cursor: pointer; box-shadow: 0 4px 12px rgba(0,0,0,0.2); display: none; z-index: 99; }
.back-to-top.show { display: block; }
.faq-item { border-bottom: 1px solid rgba(255,255,255,0.1); padding: 18px 0; }
.faq-question { font-weight: 600; cursor: pointer; display: flex; justify-content: space-between; }
.faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.3s; }
.faq-answer.open { max-height: 400px; }
.schema-breadcrumb { display: flex; gap: 8px; flex-wrap: wrap; padding: 12px 0; }
.schema-breadcrumb span { color: var(--brand-accent); }
.article-card { border-bottom: 1px solid rgba(0,0,0,0.05); padding: 20px 0; }
.article-card h3 { font-size: 1.2rem; }
.howto-step { background: var(--card-bg); padding: 20px; border-radius: 20px; margin-bottom: 16px; }