:root {
  color-scheme: light dark;
  --bg: #f7f8fb;
  --surface: rgba(255,255,255,.88);
  --text: #15171a;
  --muted: #626872;
  --line: #dfe3e8;
  --accent: #f16422;
  --accent-soft: #fff0e8;
  --blue: #1769e0;
  --shadow: 0 18px 55px rgba(22, 29, 37, .08);
}

* { box-sizing: border-box; }
html { font-size: 16px; scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at 8% 0%, rgba(241,100,34,.12), transparent 28rem),
    radial-gradient(circle at 92% 16%, rgba(23,105,224,.09), transparent 30rem),
    var(--bg);
  line-height: 1.72;
}

a { color: var(--blue); text-decoration-thickness: .08em; text-underline-offset: .18em; }
a:hover { text-decoration-thickness: .13em; }
.shell { width: min(1120px, calc(100% - 40px)); margin: 0 auto; }
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  border-bottom: 1px solid rgba(170,178,188,.42);
  background: rgba(247,248,251,.82);
  backdrop-filter: blur(18px);
}
.nav { min-height: 68px; display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.brand { display: inline-flex; align-items: center; gap: 11px; color: var(--text); text-decoration: none; font-weight: 760; letter-spacing: -.02em; }
.brand-mark { width: 34px; height: 34px; display: grid; place-items: center; color: white; background: linear-gradient(145deg,#ff7b2f,#ef4b12); border-radius: 10px; box-shadow: 0 7px 18px rgba(241,100,34,.24); }
.nav-actions { display: flex; align-items: center; gap: 15px; }
.nav-link { color: var(--muted); text-decoration: none; font-weight: 600; }
.lang-switch { display: inline-flex; padding: 3px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); }
.lang-switch button { border: 0; border-radius: 7px; padding: 7px 10px; color: var(--muted); background: transparent; font: inherit; cursor: pointer; }
.lang-switch button[aria-pressed="true"] { color: var(--text); background: white; box-shadow: 0 2px 8px rgba(0,0,0,.08); }
main { padding: 74px 0 96px; }
.eyebrow { margin: 0 0 14px; color: var(--accent); font-weight: 750; letter-spacing: .08em; text-transform: uppercase; font-size: .8rem; }
h1 { max-width: 840px; margin: 0; font-size: clamp(2.35rem, 7vw, 5.8rem); line-height: .98; letter-spacing: -.065em; }
.lede { max-width: 720px; margin: 26px 0 0; color: var(--muted); font-size: clamp(1.05rem, 2vw, 1.28rem); }
.app-grid { display: grid; grid-template-columns: repeat(12, 1fr); gap: 24px; margin-top: 55px; }
.app-card { grid-column: span 12; display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: 24px; padding: 28px; color: var(--text); text-decoration: none; border: 1px solid var(--line); border-radius: 26px; background: var(--surface); box-shadow: var(--shadow); }
.app-icon { width: 92px; aspect-ratio: 1; border-radius: 22px; object-fit: cover; box-shadow: 0 12px 25px rgba(241,100,34,.22); }
.app-card h2 { margin: 0 0 4px; font-size: 1.55rem; letter-spacing: -.025em; }
.app-card p { margin: 0; color: var(--muted); }
.arrow { font-size: 1.8rem; color: var(--accent); }
.page-head { max-width: 760px; margin-bottom: 46px; }
.page-head h1 { font-size: clamp(2.3rem, 5vw, 4.7rem); }
.updated { margin-top: 18px; color: var(--muted); font-size: .9rem; }
.content-layout { display: grid; grid-template-columns: 230px minmax(0, 730px); gap: 54px; align-items: start; }
.side-nav { position: sticky; top: 100px; display: grid; gap: 8px; }
.side-nav > div { gap: 8px; }
.side-nav > div[data-lang] { display: none; }
.side-nav > div[data-lang] a { display: block; }
.side-nav > div[data-lang] a + a { margin-top: 8px; }
.side-nav a { padding: 8px 12px; border-radius: 9px; color: var(--muted); text-decoration: none; font-size: .92rem; }
.side-nav a:hover { color: var(--text); background: var(--surface); }
.article { padding: 36px clamp(22px, 5vw, 52px); border: 1px solid var(--line); border-radius: 26px; background: var(--surface); box-shadow: var(--shadow); }
.article section + section { padding-top: 27px; margin-top: 27px; border-top: 1px solid var(--line); }
.article h2 { margin: 0 0 12px; font-size: 1.28rem; letter-spacing: -.015em; }
.article h3 { margin: 20px 0 8px; font-size: 1.02rem; }
.article p, .article li { color: #383d45; }
.article ul { padding-left: 1.3rem; }
.article li + li { margin-top: .55rem; }
.support-grid { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 18px; }
.support-card { padding: 26px; border: 1px solid var(--line); border-radius: 20px; background: var(--surface); }
.support-card h2 { margin: 0 0 8px; font-size: 1.16rem; }
.support-card p { margin: 0; color: var(--muted); }
.contact-card { margin-top: 28px; padding: 32px; border-radius: 24px; color: white; background: #171a1f; }
.contact-card a { color: #ffae7e; }
.contact-card h2 { margin-top: 0; }
.app-hero { display: grid; grid-template-columns: 130px 1fr; gap: 30px; align-items: center; }
.app-hero .app-icon { width: 130px; border-radius: 29px; }
.app-hero h1 { font-size: clamp(2.8rem, 7vw, 5.8rem); }
.quick-links { display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); gap: 18px; margin-top: 48px; }
.quick-link { padding: 28px; border: 1px solid var(--line); border-radius: 22px; background: var(--surface); color: var(--text); text-decoration: none; }
.quick-link strong { display:block; margin-bottom: 6px; font-size: 1.15rem; }
.quick-link span { color: var(--muted); }
.footer { padding: 28px 0 42px; border-top: 1px solid var(--line); color: var(--muted); font-size: .9rem; }
[data-lang] { display: none; }
html[data-language="zh"] [data-lang="zh"], html[data-language="en"] [data-lang="en"] { display: revert; }
html[data-language="zh"] .side-nav > div[data-lang="zh"], html[data-language="en"] .side-nav > div[data-lang="en"] { display: grid; }

@media (max-width: 760px) {
  .shell { width: min(100% - 28px, 1120px); }
  .nav-link { display: none; }
  main { padding-top: 48px; }
  .app-card { grid-template-columns: auto 1fr; padding: 20px; gap: 18px; }
  .app-icon { width: 70px; border-radius: 17px; }
  .arrow { display: none; }
  .content-layout { grid-template-columns: 1fr; gap: 20px; }
  .side-nav { display: none; }
  .article { padding: 28px 20px; border-radius: 20px; }
  .support-grid, .quick-links { grid-template-columns: 1fr; }
  .app-hero { grid-template-columns: 86px 1fr; gap: 18px; }
  .app-hero .app-icon { width: 86px; border-radius: 20px; }
}

@media (prefers-color-scheme: dark) {
  :root { --bg:#0f1115; --surface:rgba(27,30,36,.9); --text:#f5f6f7; --muted:#a9afb8; --line:#343942; --accent-soft:#3a2117; --blue:#65a4ff; --shadow:0 18px 55px rgba(0,0,0,.22); }
  .site-header { background:rgba(15,17,21,.83); }
  .lang-switch button[aria-pressed="true"] { background:#343942; }
  .article p, .article li { color:#d2d6db; }
}