```css
:root {
  --bg-light: #f8fafc;
  --bg-card: #ffffff;
  --text-primary: #1f2937;
  --text-secondary: #334155;
  --text-muted: #475569;
  --heading-color: #0f172a;
  --accent: #2563eb;
  --accent-dark: #1e3a8a;
  --border-light: #e2e8f0;
  --footer-bg: #0f172a;
  --footer-text: #e2e8f0;
  --footer-link: #cbd5e1;
  --btn-bg: #2563eb;
  --btn-text: #ffffff;
  --nav-bg: rgba(255,255,255,0.9);
  --shadow: 0 4px 6px -1px rgba(0,0,0,0.05);
  --accent-gradient: linear-gradient(145deg, #1e293b 0%, #0f172a 100%);
  --card-hover-shadow: 0 20px 30px -10px rgba(37, 99, 235, 0.2);
  --transition-default: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}
[data-theme="dark"] {
  --bg-light: #0b1120;
  --bg-card: #1e293b;
  --text-primary: #e2e8f0;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --heading-color: #f8fafc;
  --border-light: #334155;
  --footer-bg: #020617;
  --footer-text: #e2e8f0;
  --footer-link: #94a3b8;
  --nav-bg: rgba(15, 23, 42, 0.9);
  --accent-gradient: linear-gradient(145deg, #0f172a 0%, #020617 100%);
  --card-hover-shadow: 0 20px 30px -10px rgba(0, 0, 0, 0.6);
}
* { margin:0; padding:0; box-sizing:border-box; }
html { scroll-behavior:smooth; }
body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg-light);
  color: var(--text-primary);
  line-height: 1.7;
  transition: background 0.3s, color 0.3s;
}
a { color: var(--accent); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--accent-dark); text-decoration: underline; }
.container { max-width: 1280px; margin: 0 auto; padding: 0 20px; }
/* 导航 */
.navbar {
  position: sticky; top: 0; z-index: 50;
  background: var(--nav-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-light);
  transition: background 0.3s;
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; padding: 12px 20px; max-width: 1280px; margin:0 auto; }
.logo { font-size: 1.5rem; font-weight: 700; color: var(--heading-color); }
.logo span { color: var(--accent); }
.nav-links { display: flex; gap: 24px; align-items: center; }
.nav-links a { color: var(--text-primary); font-weight: 500; }
.nav-links a:hover { color: var(--accent); }
.search-box { display: flex; align-items: center; border:1px solid var(--border-light); border-radius: 30px; padding: 4px 8px; background: var(--bg-card); transition: border-color 0.3s, box-shadow 0.3s; }
.search-box:focus-within { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15); }
.search-box input { border:none; background: transparent; padding: 6px 8px; width: 140px; color: var(--text-primary); outline: none; }
.search-box button { background: var(--btn-bg); color: var(--btn-text); border:none; border-radius: 20px; padding: 6px 12px; cursor: pointer; font-weight:500; transition: background 0.3s; }
.search-box button:hover { background: var(--accent-dark); }
.theme-toggle { background: var(--bg-card); border:1px solid var(--border-light); color: var(--text-primary); border-radius: 30px; padding: 6px 12px; cursor: pointer; font-weight:500; transition: all 0.3s; }
.theme-toggle:hover { border-color: var(--accent); background: var(--accent); color: white; }
.hamburger { display: none; flex-direction: column; gap:5px; cursor:pointer; background: none; border:none; padding: 5px; }
.hamburger span { width: 24px; height: 2px; background: var(--text-primary); transition: all 0.3s; }
/* 移动菜单 */
.mobile-menu { display: none; flex-direction: column; background: var(--bg-card); padding: 16px; border-bottom:1px solid var(--border-light); }
.mobile-menu a { padding: 10px 0; font-weight: 500; color: var(--text-primary); }
.mobile-menu a:hover { color: var(--accent); }
/* hero banner */
.hero {
  background: var(--accent-gradient);
  color: #f8fafc;
  padding: 60px 20px;
  border-radius: 0 0 30px 30px;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(37, 99, 235, 0.3) 0%, transparent 70%);
  pointer-events: none;
}
.hero-content { max-width: 1280px; margin:0 auto; display: grid; gap: 30px; position: relative; z-index: 1; }
.hero h1 { font-size: 2.5rem; font-weight: 800; color: #ffffff; line-height:1.2; }
.hero .subhead { font-size: 1.2rem; color: #cbd5e1; max-width: 700px; }
.hero-cta { display: flex; gap: 16px; flex-wrap: wrap; margin-top: 20px; }
.btn { display: inline-block; background: var(--btn-bg); color: var(--btn-text) !important; padding: 12px 28px; border-radius: 40px; font-weight: 600; transition: all 0.2s; }
.btn:hover { background: var(--accent-dark); text-decoration:none; transform: translateY(-2px); box-shadow: 0 10px 20px rgba(0,0,0,0.2); }
.btn-outline { background: transparent; border: 2px solid #94a3b8; color: #e2e8f0 !important; }
.btn-outline:hover { background: rgba(148, 163, 184, 0.1); border-color: #e2e8f0; }
/* 卡片 */
.section { padding: 50px 0; }
.grid-2 { display: grid; grid-template-columns: repeat(2,1fr); gap: 24px; }
.grid-3 { display: grid; grid-template-columns: repeat(3,1fr); gap: 24px; }
.grid-4 { display: grid; grid-template-columns: repeat(4,1fr); gap: 20px; }
.card { background: var(--bg-card); border-radius: 16px; padding: 24px; box-shadow: var(--shadow); border:1px solid var(--border-light); transition: transform 0.3s, box-shadow 0.3s; position: relative; overflow: hidden; }
.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), transparent);
  opacity: 0;
  transition: opacity 0.3s;
}
.card:hover { transform: translateY(-5px); box-shadow: var(--card-hover-shadow); }
.card:hover::before { opacity: 1; }
.card h3 { color: var(--heading-color); margin-bottom: 8px; font-size: 1.25rem; }
.card p { color: var(--text-secondary); }
.card a { font-weight: 600; }
/* 标题 */
h2 { font-size: 2rem; color: var(--heading-color); font-weight: 700; margin-bottom: 20px; position: relative; }
h2:after { content:''; display:block; width: 60px; height: 4px; background: var(--accent); margin-top: 8px; border-radius: 2px; transition: width 0.3s; }
h2:hover:after { width: 100px; }
h3 { color: var(--heading-color); font-weight: 600; }
h4 { color: var(--heading-color); font-weight: 600; }
/* 表格 */
table { width: 100%; border-collapse: collapse; background: var(--bg-card); border-radius: 12px; overflow: hidden; box-shadow: var(--shadow); }
th, td { padding: 14px 16px; text-align: left; border-bottom: 1px solid var(--border-light); }
th { background: var(--accent); color: white; font-weight:600; }
td { color: var(--text-primary); }
/* FAQ */
.faq-item { border-bottom:1px solid var(--border-light); padding: 14px 0; transition: background 0.3s; }
.faq-item:hover { background: rgba(37, 99, 235, 0.05); }
.faq-question { color: var(--heading-color); font-weight: 600; cursor: pointer; display: flex; justify-content: space-between; align-items: center; padding: 8px; border-radius: 8px; transition: color 0.3s; }
.faq-question:hover { color: var(--accent); }
.faq-answer { margin-top: 10px; color: var(--text-secondary); display: none; padding: 0 8px; }
.faq-item.active .faq-answer { display: block; animation: fadeIn 0.3s ease; }
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-10px); }
  to { opacity: 1; transform: translateY(0); }
}
/* footer */
footer { background: var(--footer-bg); color: var(--footer-text); padding: 40px 0 20px; margin-top: 60px; }
footer a { color: var(--footer-link); transition: color 0.3s; }
footer a:hover { color: white; }
.footer-grid { display: grid; grid-template-columns: repeat(4,1fr); gap: 30px; }
.footer-bottom { border-top:1px solid #334155; margin-top: 30px; padding-top: 20px; font-size:0.9rem; color:#94a3b8; }
/* 面包屑 */
.breadcrumb { background: transparent; padding: 12px 0; color: var(--text-secondary); font-size:0.9rem; }
.breadcrumb a { color: var(--accent); }
/* 交互 */
.back-to-top { position: fixed; bottom: 30px; right: 30px; background: var(--accent); color: white; width: 40px; height: 40px; border-radius: 50%; display: flex; align-items: center; justify-content: center; cursor: pointer; border:none; font-size: 1.2rem; box-shadow: 0 4px 10px rgba(0,0,0,0.2); z-index: 99; transition: all 0.3s; }
.back-to-top:hover { background: var(--accent-dark); transform: translateY(-3px); box-shadow: 0 6px 15px rgba(0,0,0,0.3); }
.scroll-animate { opacity: 0; transform: translateY(20px); transition: opacity 0.6s, transform 0.6s; }
.scroll-animate.visible { opacity: 1; transform: translateY(0); }
/* 响应式 */
@media (max-width: 900px) { 
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .nav-links, .search-box { display: none; }
  .hamburger { display: flex; }
  .mobile-menu.open { display: flex; }
  .hero h1 { font-size: 2.2rem; }
}
@media (max-width: 600px) { 
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .hero h1 { font-size: 2rem; }
  .hero { padding: 40px 16px; }
  .footer-grid { grid-template-columns: 1fr; }
  .nav-inner { padding: 10px 16px; }
  .section { padding: 30px 0; }
  h2 { font-size: 1.7rem; }
}
```