:root {
  --ink: #111512;
  --paper: #f3f4ef;
  --surface: #fffefa;
  --muted: #666d67;
  --line: #cdd2cd;
  --lime: #b9ef6f;
  --green: #2e7d49;
  --coral: #ff7a59;
  --amber: #ffd166;
  --blue: #82aef1;
  --max: 1200px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; min-width: 320px; color: var(--ink); background: var(--paper); font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif; letter-spacing: 0; }
a { color: inherit; }
button, input { font: inherit; letter-spacing: 0; }
svg { width: 18px; height: 18px; stroke-width: 1.8; }
.shell { width: min(calc(100% - 48px), var(--max)); margin: 0 auto; }
.skip-link { position: fixed; top: -70px; left: 12px; z-index: 100; padding: 11px 14px; color: var(--ink); background: var(--surface); }
.skip-link:focus { top: 12px; }
.site-header { height: 68px; padding: 0 max(24px, calc((100vw - var(--max)) / 2)); display: flex; align-items: center; justify-content: space-between; gap: 28px; color: #f7faf7; background: var(--ink); border-bottom: 1px solid #384039; }
.brand { display: inline-flex; align-items: center; gap: 10px; text-decoration: none; font-weight: 760; }
.brand-mark { width: 34px; height: 34px; display: grid; place-items: center; color: var(--ink); background: var(--lime); font-size: .75rem; font-weight: 900; }
.site-header nav { display: flex; gap: 26px; margin-left: auto; }
.site-header nav a { color: #c3cac4; text-decoration: none; font-size: .77rem; }
.site-header nav a:hover { color: var(--lime); }
.locale-link { min-height: 34px; padding: 0 10px; display: inline-flex; align-items: center; border: 1px solid #4b554d; color: #eff3ef; text-decoration: none; font-size: .7rem; font-weight: 750; }
.button { min-height: 46px; padding: 0 17px; display: inline-flex; align-items: center; justify-content: center; gap: 9px; border: 1px solid var(--ink); text-decoration: none; font-size: .78rem; font-weight: 800; }
.button.primary { color: var(--ink); background: var(--lime); }
.button.secondary { color: var(--surface); background: transparent; border-color: #697269; }
.hero { min-height: 690px; padding: 82px 0 72px; color: #f7faf7; background-color: var(--ink); background-image: linear-gradient(#202721 1px, transparent 1px), linear-gradient(90deg, #202721 1px, transparent 1px); background-size: 64px 64px; }
.hero-grid { display: grid; grid-template-columns: .8fr 1.2fr; gap: 52px; align-items: center; }
.kicker, .section-code { margin: 0 0 20px; color: var(--lime); font: 800 .67rem ui-monospace, SFMono-Regular, Menlo, monospace; text-transform: uppercase; }
.hero h1 { max-width: 650px; margin: 0; font-size: clamp(3.3rem, 4.8vw, 5.2rem); line-height: .98; font-weight: 780; }
.hero h1.zh-display span { display: block; white-space: nowrap; }
.hero-lede { max-width: 570px; margin: 28px 0 0; color: #c1c8c2; font-size: 1.02rem; line-height: 1.7; }
.hero-actions { margin-top: 32px; display: flex; flex-wrap: wrap; gap: 10px; }
.hero-note { margin: 18px 0 0; color: #8f9991; font-size: .69rem; line-height: 1.5; }
.product-shot { min-width: 0; margin: 0; overflow: hidden; border: 1px solid #536056; background: #eef1ed; box-shadow: 0 32px 80px rgba(0, 0, 0, .34); transform: translateY(16px); }
.shot-bar { min-height: 42px; padding: 0 13px; display: flex; align-items: center; justify-content: space-between; color: #e1e8e2; background: #202923; font: 750 .58rem ui-monospace, SFMono-Regular, Menlo, monospace; }
.shot-bar b { color: var(--lime); }
.product-shot img { width: 100%; height: auto; display: block; }
.signal-band { color: var(--ink); background: var(--lime); border-bottom: 1px solid var(--ink); }
.signal-grid { min-height: 70px; display: grid; grid-template-columns: repeat(4, 1fr); }
.signal-grid div { padding: 0 18px; display: flex; align-items: center; justify-content: center; gap: 10px; border-right: 1px solid rgba(17, 21, 18, .35); text-align: center; }
.signal-grid div:last-child { border-right: 0; }
.signal-grid strong { font-size: 1.3rem; }
.signal-grid span { font-size: .68rem; font-weight: 780; text-transform: uppercase; }
.section { padding: 100px 0; }
.section-heading { max-width: 810px; margin-bottom: 48px; }
.section-heading h2 { margin: 0; font-size: clamp(2.25rem, 4.5vw, 4.6rem); line-height: 1.05; }
.section-heading > p:last-child { max-width: 680px; margin: 22px 0 0; color: var(--muted); line-height: 1.72; }
.problem-list { border-top: 1px solid var(--ink); }
.problem-row { min-height: 150px; display: grid; grid-template-columns: 70px 1fr 1fr; gap: 34px; align-items: center; border-bottom: 1px solid var(--line); }
.problem-row > span { color: var(--green); font: 800 .7rem ui-monospace, SFMono-Regular, Menlo, monospace; }
.problem-row h3 { margin: 0; font-size: 1.45rem; }
.problem-row p { margin: 0; color: var(--muted); line-height: 1.65; font-size: .87rem; }
.architecture { color: #eef4ef; background: #18201b; }
.architecture .section-heading > p:last-child { color: #aeb8b0; }
.layer-flow { display: grid; grid-template-columns: repeat(4, 1fr); border: 1px solid #455047; }
.layer { min-height: 250px; padding: 22px; position: relative; display: flex; flex-direction: column; border-right: 1px solid #455047; }
.layer:last-child { border-right: 0; }
.layer > span { color: var(--lime); font: 800 .65rem ui-monospace, SFMono-Regular, Menlo, monospace; }
.layer h3 { margin: auto 0 11px; font-size: 1.35rem; }
.layer p { min-height: 62px; margin: 0; color: #aeb8b0; font-size: .75rem; line-height: 1.65; }
.layer-tags { margin-top: 18px; display: flex; flex-wrap: wrap; gap: 5px; }
.layer-tags b { padding: 5px 7px; color: #dbe3dc; background: #28332b; font-size: .55rem; }
.modes { background: #e6e9e2; }
.mode-table { border-top: 1px solid var(--ink); }
.mode-row { min-height: 120px; display: grid; grid-template-columns: 170px 1fr 1fr; gap: 34px; align-items: center; border-bottom: 1px solid #c5cac3; }
.mode-row > strong { font-size: .75rem; text-transform: uppercase; }
.mode-row h3 { margin: 0 0 8px; font-size: 1.15rem; }
.mode-row p { margin: 0; color: var(--muted); font-size: .8rem; line-height: 1.6; }
.mode-badge { width: max-content; padding: 7px 9px; font-size: .62rem; font-weight: 800; }
.mode-badge.direct { background: var(--lime); }
.mode-badge.handoff { background: var(--amber); }
.mode-badge.observed { color: #fff; background: #405b88; }
.environment { background: var(--surface); }
.environment-grid { display: grid; grid-template-columns: 1fr 1fr; border: 1px solid var(--ink); }
.environment-block { min-height: 330px; padding: 30px; display: flex; flex-direction: column; }
.environment-block + .environment-block { border-left: 1px solid var(--ink); }
.environment-label { width: max-content; padding: 6px 8px; font-size: .6rem; font-weight: 850; }
.environment-label.production { color: #fff; background: var(--green); }
.environment-label.isolated { background: var(--amber); }
.environment-block h3 { margin: 62px 0 14px; font-size: 2rem; }
.environment-block p { max-width: 460px; margin: 0; color: var(--muted); line-height: 1.7; }
.environment-block ul { margin: auto 0 0; padding: 22px 0 0; list-style: none; border-top: 1px solid var(--line); }
.environment-block li { margin: 9px 0; font-size: .76rem; }
.faq { background: var(--paper); }
.faq-grid { display: grid; grid-template-columns: .55fr 1fr; gap: 80px; }
.faq-list { border-top: 1px solid var(--ink); }
.faq-list details { border-bottom: 1px solid var(--line); }
.faq-list summary { min-height: 70px; display: flex; align-items: center; justify-content: space-between; gap: 20px; cursor: pointer; font-weight: 760; list-style: none; }
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary::after { content: "+"; font-size: 1.2rem; }
.faq-list details[open] summary::after { content: "−"; }
.faq-list p { margin: 0; padding: 0 38px 24px 0; color: var(--muted); line-height: 1.7; font-size: .84rem; }
.closing { padding: 86px 0; color: #f5f8f5; background: var(--ink); }
.closing-grid { display: grid; grid-template-columns: 1fr auto; gap: 46px; align-items: end; }
.closing h2 { max-width: 820px; margin: 0; font-size: clamp(2.4rem, 4.8vw, 5rem); line-height: 1.02; }
.closing p { margin: 20px 0 0; color: #aeb8b0; }
footer { padding: 22px 0; color: #aeb8b0; background: var(--ink); border-top: 1px solid #384039; }
.footer-row { display: flex; align-items: center; justify-content: space-between; gap: 20px; font-size: .7rem; }
.footer-row div { display: flex; gap: 20px; }
@media (max-width: 900px) {
  .site-header nav { display: none; }
  .hero-grid { grid-template-columns: 1fr; gap: 40px; }
  .product-shot { transform: none; }
  .problem-row { grid-template-columns: 52px 1fr; padding: 24px 0; }
  .problem-row p { grid-column: 2; }
  .layer-flow { grid-template-columns: 1fr 1fr; }
  .layer:nth-child(2) { border-right: 0; }
  .layer:nth-child(-n+2) { border-bottom: 1px solid #455047; }
  .faq-grid { grid-template-columns: 1fr; gap: 36px; }
}
@media (max-width: 640px) {
  .shell { width: min(calc(100% - 32px), var(--max)); }
  .site-header { padding: 0 16px; }
  .hero { min-height: auto; padding: 66px 0 52px; }
  .hero h1 { font-size: clamp(2.75rem, 12vw, 4.2rem); }
  .signal-grid { grid-template-columns: 1fr 1fr; }
  .signal-grid div { min-height: 62px; border-bottom: 1px solid rgba(17, 21, 18, .35); }
  .signal-grid div:nth-child(2) { border-right: 0; }
  .section { padding: 72px 0; }
  .layer-flow { grid-template-columns: 1fr; }
  .layer, .layer:nth-child(2) { min-height: 210px; border-right: 0; border-bottom: 1px solid #455047; }
  .layer:last-child { border-bottom: 0; }
  .mode-row { grid-template-columns: 1fr; gap: 12px; padding: 22px 0; }
  .environment-grid { grid-template-columns: 1fr; }
  .environment-block { min-height: 300px; padding: 22px; }
  .environment-block + .environment-block { border-left: 0; border-top: 1px solid var(--ink); }
  .closing-grid { grid-template-columns: 1fr; align-items: start; }
  .footer-row { align-items: flex-start; flex-direction: column; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }