/* 基础 */
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: 100px; }
body { font-family: "PingFang SC", "Microsoft YaHei", sans-serif; line-height: 1.6; color: #333; background: #f8f9fa; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; }
img { display: block; max-width: 100%; height: auto; }
button { font: inherit; }
a:focus-visible, button:focus-visible, [tabindex]:focus-visible { outline: 3px solid #2563eb; outline-offset: 5px; }
.container { width: 100%; max-width: 1200px; margin-inline: auto; padding-inline: 20px; }
.visually-hidden, .skip-link:not(:focus) { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }
.skip-link:focus { position: fixed; top: 8px; left: 8px; z-index: 1100; padding: 10px 20px; color: #fff; background: #1e3a8a; }
/* 页头 */
.site-header { position: sticky; top: 0; z-index: 1000; background: #fff; box-shadow: 0 2px 10px #0000000d; }
.header-inner { display: flex; justify-content: space-between; align-items: center; min-height: 68px; padding-block: 15px; }
.logo, .footer-logo { font-size: 24px; font-weight: 700; color: #1e3a8a; }
.logo span { color: #3b82f6; }
.main-nav ul { display: flex; gap: 30px; }
.main-nav a { position: relative; padding-block: 5px; color: #4b5563; font-weight: 500; transition: color .2s; }
.main-nav a::after { content: ""; position: absolute; bottom: 0; left: 0; width: 0; height: 2px; background: #3b82f6; transition: width .2s; }
.main-nav a:hover { color: #3b82f6; }
.main-nav a:hover::after { width: 100%; }
.menu-toggle { display: none; border: 0; background: transparent; color: #4b5563; font-size: 24px; cursor: pointer; }
/* 首屏 */
main { padding-top: 40px; padding-bottom: 40px; }
.hero { margin-bottom: 60px; padding: 60px 40px; border-radius: 16px; color: #fff; text-align: center; background: linear-gradient(135deg, #1e3a8a, #3b82f6); }
.hero h1 { font-size: 32px; line-height: 1.6; }
.hero-subtitle { max-width: 800px; margin: 0 auto 40px; font-size: 18px; opacity: .9; }
.exchange-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 30px; margin-top: 40px; }
.exchange-card { display: flex; flex-direction: column; padding: 30px; border-radius: 12px; background: #ffffff1a; backdrop-filter: blur(10px); }
.exchange-card h2 { margin-bottom: 20px; font-size: 28px; }
.exchange-card p { flex: 1; margin-bottom: 25px; opacity: .9; }
.button-group { display: flex; justify-content: center; gap: 15px; }
.button { display: inline-block; padding: 12px 28px; border: 2px solid transparent; border-radius: 8px; font-size: 16px; font-weight: 600; transition: background .2s, border-color .2s; }
.button-primary { border-color: #10b981; background: #10b981; }
.button-primary:hover { border-color: #0da271; background: #0da271; }
.button-secondary { border-color: #ffffff4d; }
.button-secondary:hover { border-color: #fff; background: #ffffff0a; }
.hero a:focus-visible { outline-color: #fff; }
/* 内容栏目 */
.section { margin-bottom: 60px; }
.section-title { margin-bottom: 30px; color: #1f2937; font-size: 28px; font-weight: 700; text-align: center; }
.section-note { margin-top: 14px; color: #6b7280; font-size: 13px; text-align: center; }
.market-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 20px; }
.market-card, .news-card, .table-wrap, .guide-step { border-radius: 12px; background: #fff; box-shadow: 0 4px 6px #0000000d; }
.market-card { padding: 20px; transition: transform .2s, box-shadow .2s; }
.market-card:hover { transform: translateY(-5px); box-shadow: 0 10px 20px #0000001a; }
.coin-header { display: flex; justify-content: space-between; align-items: center; gap: 8px; margin-bottom: 15px; }
.coin-header h3, .coin-header p { font-size: 18px; font-weight: 700; }
.coin-header p { white-space: nowrap; }
.change { display: inline-block; padding: 3px 8px; border-radius: 4px; font-size: 14px; font-weight: 600; }
.change-up { color: #15803d; background: #dcfce7; }
.change-down { color: #dc2626; background: #fee2e2; }
.news-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 25px; }
.news-card { overflow: hidden; }
.news-image { display: flex; height: 180px; align-items: center; justify-content: center; overflow: hidden; background: #e5e7eb; }
.news-image img { width: 100%; height: 100%; object-fit: cover; }
.news-content { padding: 20px; }
.news-content h3 { margin-bottom: 10px; font-size: 18px; line-height: 1.4; }
.news-content p { margin-bottom: 15px; color: #6b7280; line-height: 1.5; }
.news-content time { color: #707988; font-size: 14px; }
.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; text-align: left; }
th, td { padding: 20px; border-bottom: 1px solid #e5e7eb; }
thead th { color: #374151; background: #f9fafb; }
tbody th { font-weight: 400; }
tbody tr:last-child > * { border-bottom: 0; }
.feature-yes { color: #0b8761; font-weight: 700; }
.guide-steps { display: flex; flex-wrap: wrap; justify-content: center; gap: 30px; }
.guide-step { flex: 1; min-width: 250px; max-width: 300px; padding: 30px; text-align: center; }
.step-number { display: inline-flex; width: 50px; height: 50px; align-items: center; justify-content: center; margin-bottom: 20px; border-radius: 50%; color: #fff; background: #3b82f6; font-size: 24px; font-weight: 700; }
.guide-step h3 { margin-bottom: 15px; font-size: 20px; }
/* 页脚与说明页 */
.site-footer { padding: 50px 0 30px; color: #f9fafb; background: #1f2937; }
.footer-inner { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 40px; }
.footer-about { max-width: 300px; }
.footer-logo { display: inline-block; margin-bottom: 20px; color: #f9fafb; }
.footer-logo span { color: #60a5fa; }
.footer-links { display: flex; flex-wrap: wrap; gap: 40px; }
.footer-links h3 { margin-bottom: 20px; color: #d1d5db; font-size: 18px; }
.footer-links li { margin-bottom: 12px; }
.footer-links a { color: #b4bdca; }
.footer-links a:hover { color: #60a5fa; }
.footer-bottom { margin-top: 50px; padding-top: 20px; border-top: 1px solid #374151; color: #b4bdca; font-size: 14px; text-align: center; }
.info-page { max-width: 900px; min-height: 70vh; }
.info-page h1 { margin-bottom: 30px; }
.info-page section { margin-bottom: 30px; padding: 30px; border-radius: 12px; background: #fff; }
.info-page h2 { margin-bottom: 12px; }
.info-page p + p { margin-top: 12px; }
/* 平板与手机 */
@media (max-width: 1100px) {
  .market-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .main-nav ul { gap: 20px; }
}
@media (max-width: 768px) {
  .hero { padding: 40px 20px; }
  .hero-subtitle { font-size: 16px; }
  .section-title { font-size: 24px; }
  .exchange-grid { grid-template-columns: 1fr; }
  .button-group { flex-direction: column; align-items: center; }
  .button { width: 100%; max-width: 250px; }
  .news-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  table { min-width: 600px; }
  .guide-steps { flex-direction: column; align-items: center; }
  .guide-step { width: 100%; max-width: 100%; min-width: 0; }
  .footer-inner { flex-direction: column; }
  .footer-about { max-width: 100%; }
  .main-nav ul { gap: 16px; }
}
@media (max-width: 640px) {
  .header-inner { min-height: 58px; padding-block: 10px; }
  .main-nav { width: 100%; padding-top: 10px; }
  .header-inner { flex-wrap: wrap; }
  .main-nav ul { flex-wrap: wrap; gap: 10px 20px; }
  .js .menu-toggle { display: block; }
  .js .main-nav { display: none; position: absolute; top: 100%; left: 0; padding: 20px; background: #fff; box-shadow: 0 5px 10px #0000001a; }
  .js .main-nav.is-open { display: block; }
  .js .main-nav ul { flex-direction: column; gap: 15px; }
  .hero { padding: 30px 15px; }
  .exchange-card { padding: 20px 15px; }
  .exchange-card h2 { font-size: 28px; }
  .button { padding-inline: 20px; }
  .market-grid, .news-grid { grid-template-columns: 1fr; }
  .market-card { padding: 20px; }
  .footer-links { gap: 28px; }
  .footer-links h3 { font-size: 16px; }
  .footer-links a { font-size: 14px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::after { transition: none !important; }
}