:root {
  color-scheme: light;
  --ink: #102735;
  --muted: #58707d;
  --paper: #f4f8f7;
  --white: #fff;
  --teal: #087f78;
  --teal-deep: #075b59;
  --aqua: #69d6c4;
  --blue: #2c6680;
  --line: rgba(16, 39, 53, 0.13);
  --shadow: 0 24px 70px rgba(16, 39, 53, 0.1);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-width: 320px;
  color: var(--ink);
  background: var(--paper);
  font-family: Inter, "Microsoft YaHei", "PingFang SC", system-ui, -apple-system, sans-serif;
  font-size: 16px;
  line-height: 1.72;
}
a { color: inherit; }
button { font: inherit; }
.shell { width: min(1120px, calc(100% - 40px)); margin-inline: auto; }
.skip-link { position: fixed; left: 18px; top: -80px; z-index: 20; padding: 10px 16px; background: #fff; border-radius: 8px; }
.skip-link:focus { top: 12px; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  border-bottom: 1px solid var(--line);
  background: rgba(244, 248, 247, 0.92);
  backdrop-filter: blur(16px);
}
.header-inner { display: flex; min-height: 78px; align-items: center; gap: 30px; }
.brand { display: inline-flex; align-items: center; gap: 11px; text-decoration: none; font-weight: 800; letter-spacing: -0.02em; }
.brand-mark { display: grid; width: 36px; height: 36px; place-items: center; border-radius: 13px 13px 4px; color: #fff; background: linear-gradient(145deg, var(--teal), var(--teal-deep)); font-family: Georgia, serif; font-size: 21px; }
.nav { display: flex; margin-left: auto; align-items: center; gap: 24px; }
.nav a { color: var(--muted); text-decoration: none; font-size: 14px; font-weight: 700; }
.nav a:hover, .nav a[aria-current="page"] { color: var(--teal-deep); }
.language-switch { display: inline-flex; padding: 4px; border: 1px solid var(--line); border-radius: 999px; background: #fff; }
.language-switch button { min-width: 46px; padding: 6px 10px; border: 0; border-radius: 999px; color: var(--muted); background: transparent; cursor: pointer; font-size: 13px; font-weight: 800; }
.language-switch button[aria-pressed="true"] { color: #fff; background: var(--teal-deep); }
.menu-button { display: none; width: 42px; height: 42px; border: 1px solid var(--line); border-radius: 50%; background: #fff; cursor: pointer; }

.js [data-language-panel] { display: none; }
.js[data-locale="zh-CN"] [data-language-panel="zh-CN"],
.js[data-locale="en"] [data-language-panel="en"] { display: block; }

.hero {
  position: relative;
  overflow: hidden;
  padding: 94px 0 82px;
  background:
    radial-gradient(circle at 86% 14%, rgba(105, 214, 196, 0.42), transparent 26rem),
    radial-gradient(circle at 8% 88%, rgba(44, 102, 128, 0.16), transparent 24rem),
    linear-gradient(145deg, #f8fbfa, #eaf4f1);
}
.hero::after { position: absolute; right: -120px; bottom: -190px; width: 460px; height: 460px; border: 74px solid rgba(8, 127, 120, 0.08); border-radius: 50%; content: ""; }
.hero-grid { position: relative; z-index: 1; display: grid; grid-template-columns: minmax(0, 1.25fr) minmax(280px, .75fr); gap: 70px; align-items: end; }
.eyebrow { margin: 0 0 18px; color: var(--teal); font-size: 13px; font-weight: 850; letter-spacing: .17em; text-transform: uppercase; }
h1, h2, h3 { font-family: Georgia, "Songti SC", serif; font-weight: 500; }
h1 { max-width: 800px; margin: 0; font-size: clamp(46px, 7vw, 82px); line-height: 1.03; letter-spacing: -.04em; }
.lead { max-width: 720px; margin: 28px 0 0; color: var(--muted); font-size: clamp(18px, 2.1vw, 22px); }
.hero-note { padding: 30px; border: 1px solid rgba(255,255,255,.74); border-radius: 28px 28px 8px; background: rgba(255,255,255,.78); box-shadow: var(--shadow); }
.hero-note span { color: var(--teal); font-size: 12px; font-weight: 850; letter-spacing: .14em; }
.hero-note strong { display: block; margin: 16px 0 10px; font-family: Georgia, "Songti SC", serif; font-size: 30px; line-height: 1.2; }
.hero-note p { margin: 0; color: var(--muted); }

.section { padding: 78px 0; }
.section-heading { display: grid; grid-template-columns: minmax(0, .7fr) minmax(320px, 1.3fr); gap: 54px; align-items: end; margin-bottom: 38px; }
.section-heading h2 { margin: 0; font-size: clamp(36px, 5vw, 58px); line-height: 1.08; }
.section-heading p { margin: 0; color: var(--muted); }
.principles, .article-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px; }
.principle, .article-card { border: 1px solid var(--line); border-radius: 22px 22px 7px; background: rgba(255,255,255,.82); box-shadow: 0 14px 38px rgba(16,39,53,.06); }
.principle { padding: 28px; }
.principle b { display: inline-grid; width: 38px; height: 38px; place-items: center; border-radius: 50%; color: var(--teal-deep); background: rgba(105,214,196,.22); }
.principle h3, .article-card h3 { margin: 22px 0 10px; font-size: 25px; line-height: 1.25; }
.principle p, .article-card p { margin: 0; color: var(--muted); }
.knowledge-section { color: #fff; background: #102735; }
.knowledge-section .section-heading p, .knowledge-section .article-card p { color: rgba(255,255,255,.68); }
.article-card { display: flex; min-height: 310px; flex-direction: column; padding: 28px; color: #fff; background: linear-gradient(160deg, rgba(255,255,255,.08), rgba(255,255,255,.025)); }
.article-card small { color: var(--aqua); font-size: 12px; font-weight: 800; letter-spacing: .11em; text-transform: uppercase; }
.article-card a { margin-top: auto; padding-top: 28px; color: var(--aqua); text-underline-offset: 5px; font-weight: 800; }
.boundary { display: grid; grid-template-columns: 1fr 1fr; gap: 34px; padding: 38px; border-left: 4px solid var(--teal); background: #fff; box-shadow: var(--shadow); }
.boundary h2 { margin: 0; font-size: 34px; }
.boundary p { margin: 0; color: var(--muted); }

.page-hero { padding: 84px 0 60px; color: #fff; background: linear-gradient(135deg, #102735, #0d615e); }
.page-hero h1 { font-size: clamp(42px, 6vw, 70px); }
.page-hero .lead { color: rgba(255,255,255,.72); }
.article-layout { display: grid; grid-template-columns: minmax(0, 1fr) 260px; gap: 64px; align-items: start; padding: 72px 0; }
.article-body h2 { margin: 44px 0 12px; font-size: 31px; }
.article-body h2:first-child { margin-top: 0; }
.article-body p { color: #334f5c; }
.source-box { position: sticky; top: 110px; padding: 24px; border: 1px solid var(--line); border-radius: 18px; background: #fff; }
.source-box h2 { margin: 0 0 16px; font-size: 22px; }
.source-box ul { display: grid; gap: 12px; margin: 0; padding-left: 19px; }
.source-box a { color: var(--teal-deep); text-underline-offset: 3px; }
.notice { margin-top: 42px; padding: 22px; border-left: 3px solid var(--teal); background: rgba(105,214,196,.13); color: #334f5c; }

.faq-list { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; padding: 68px 0 82px; }
.faq-list details { align-self: start; border: 1px solid var(--line); border-radius: 18px; background: #fff; }
.faq-list summary { position: relative; padding: 22px 54px 22px 24px; cursor: pointer; list-style: none; font-weight: 800; }
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary::after { position: absolute; right: 22px; color: var(--teal); content: "+"; font-size: 22px; }
.faq-list details[open] summary::after { content: "−"; }
.faq-list details p { margin: 0; padding: 0 24px 24px; color: var(--muted); }

.site-footer { padding: 34px 0; color: rgba(255,255,255,.68); background: #0a1e29; }
.footer-inner { display: flex; justify-content: space-between; gap: 28px; }
.footer-inner strong { color: #fff; }
.footer-inner p { max-width: 680px; margin: 0; text-align: right; }

@media (max-width: 840px) {
  .menu-button { display: inline-grid; place-items: center; }
  .nav { position: absolute; top: 78px; right: 20px; left: 20px; display: none; margin: 0; padding: 20px; border: 1px solid var(--line); border-radius: 18px; background: #fff; box-shadow: var(--shadow); }
  .nav.is-open { display: grid; }
  .language-switch { margin-left: auto; }
  .hero-grid, .section-heading, .boundary, .article-layout { grid-template-columns: 1fr; }
  .hero-grid { gap: 42px; }
  .principles, .article-grid { grid-template-columns: 1fr; }
  .article-card { min-height: 240px; }
  .source-box { position: static; }
}

@media (max-width: 620px) {
  .shell { width: min(100% - 28px, 1120px); }
  .header-inner { gap: 12px; }
  .brand span:last-child { display: none; }
  .hero { padding: 66px 0 60px; }
  .section { padding: 60px 0; }
  .faq-list { grid-template-columns: 1fr; }
  .footer-inner { flex-direction: column; }
  .footer-inner p { text-align: left; }
}

@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }