:root {
  --ink: #111214;
  --text: #3f4146;
  --muted: #71747b;
  --line: #e5e6e9;
  --soft: #f7f7f8;
  --accent: #5b5bd6;
  --accent-hover: #4949bd;
  --white: #ffffff;
  --display: "Helvetica Neue", -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
  --body: -apple-system, BlinkMacSystemFont, "Helvetica Neue", "Segoe UI", "PingFang SC", "Source Han Sans SC", "Noto Sans SC", "Microsoft YaHei", sans-serif;
  --zh: "Hiragino Sans GB", "PingFang SC", "Source Han Sans SC", "Noto Sans CJK SC", "Microsoft YaHei", sans-serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --header-height: 94px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--header-height) + 24px); }
body {
  margin: 0;
  color: var(--text);
  background: var(--white);
  font-family: var(--body);
  font-size: 16px;
  line-height: 1.72;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
button { font: inherit; }
strong { color: var(--ink); }
code { padding: 0.14em 0.38em; border-radius: 4px; color: var(--ink); background: var(--soft); font-family: var(--mono); font-size: 0.88em; }
a:focus-visible,
button:focus-visible,
summary:focus-visible,
.install-command:focus-visible { outline: 2px solid var(--accent); outline-offset: 4px; }

.site-header {
  position: sticky;
  z-index: 10;
  top: 0;
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(12px);
}
.header-inner,
main,
.site-footer { width: min(1180px, calc(100% - 64px)); margin: 0 auto; }
.header-inner { display: flex; min-height: var(--header-height); align-items: center; justify-content: space-between; gap: 36px; }
.brand { display: inline-flex; flex: 0 0 auto; align-items: center; gap: 14px; }
.brand-logo { display: block; width: 52px; height: 52px; flex: 0 0 auto; }
.brand-copy { display: flex; min-width: 0; flex-direction: column; justify-content: center; }
.brand-name { color: var(--ink); font-family: var(--display); font-size: 22px; font-weight: 600; letter-spacing: -0.025em; line-height: 1.08; white-space: nowrap; }
.brand-tagline { margin-top: 7px; color: var(--muted); font-family: var(--zh); font-size: 14px; font-weight: 300; letter-spacing: 0; line-height: 1.25; }
.site-nav { display: flex; min-width: 0; align-items: center; justify-content: flex-end; gap: clamp(13px, 1.55vw, 22px); color: #4f5258; font-size: 12.5px; white-space: nowrap; }
.site-nav a { position: relative; padding: 12px 0; }
.site-nav a::after { position: absolute; right: 0; bottom: 7px; left: 0; height: 1px; background: var(--ink); content: ""; transform: scaleX(0); transform-origin: right; transition: transform 160ms ease; }
.site-nav a:hover { color: var(--ink); }
.site-nav a:hover::after,
.site-nav a:focus-visible::after { transform: scaleX(1); transform-origin: left; }
.site-nav .nav-feedback { margin-left: 2px; color: var(--muted); }
.nav-toggle { display: none; border: 0; padding: 8px; color: var(--ink); background: transparent; cursor: pointer; }
.nav-toggle-label { font-size: 13px; }
.nav-toggle-lines { display: inline-block; width: 18px; height: 12px; margin-left: 8px; border-top: 1px solid currentColor; border-bottom: 1px solid currentColor; vertical-align: -1px; }

.hero { display: grid; grid-template-columns: minmax(0, 1fr) minmax(380px, 0.84fr); gap: clamp(52px, 7vw, 92px); align-items: start; padding: 78px 0 92px; }
.hero-copy { max-width: 620px; }
.section-kicker,
.command-label { margin: 0; color: var(--accent); font-family: var(--display); font-size: 11px; font-weight: 600; letter-spacing: 0.11em; line-height: 1.4; text-transform: uppercase; }
.hero h1,
.install-panel h2,
.section-heading h2 { margin: 0; color: var(--ink); font-family: var(--display); font-weight: 600; letter-spacing: -0.04em; }
.hero h1 { max-width: 600px; margin-top: 13px; font-size: clamp(29px, 2.8vw, 37px); line-height: 1.14; }
.hero-copy > p { margin: 20px 0 0; }
.hero-functions { margin: 12px 0 0; padding-left: 22px; }
.hero-functions li { margin: 8px 0; padding-left: 4px; }
.hero-copy .term-note { margin-top: 12px; color: var(--muted); font-size: 13px; }

.install-panel { border: 1px solid var(--line); border-radius: 14px; padding: 23px 26px; background: var(--white); box-shadow: 0 18px 46px rgba(17, 18, 20, 0.06); font-size: 14px; line-height: 1.55; }
.install-panel h2 { margin-top: 7px; font-size: 26px; line-height: 1.2; }
.button { display: inline-flex; min-height: 44px; align-items: center; justify-content: center; border: 1px solid transparent; border-radius: 8px; padding: 0 18px; cursor: pointer; font-weight: 600; line-height: 1.2; }
.button--primary { margin-top: 17px; color: var(--white); background: var(--accent); }
.button--primary:hover { background: var(--accent-hover); }
.download-meta { margin: 10px 0 0; color: var(--muted); font-size: 12px; }
.install-steps { margin: 15px 0 0; padding-left: 22px; }
.install-steps li { margin: 5px 0; padding-left: 4px; }
.command-wrap { margin-top: 15px; }
.command-label { color: var(--muted); }
.install-command { margin-top: 8px; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); padding: 12px 0; color: var(--ink); font-size: 12.5px; line-height: 1.58; }
.copy-helper { margin: 9px 0 0; color: var(--muted); font-size: 12px; }
.button--copy { min-height: 36px; margin-top: 9px; border-color: var(--line); padding: 0 14px; color: var(--ink); background: var(--white); font-size: 12.5px; }
.button--copy:hover { border-color: #b9bbc1; background: var(--soft); }
.button--copy[data-state="copied"] { border-color: #b8d9c2; color: #276339; background: #f4faf6; }
.copy-status { min-height: 1.5em; margin: 7px 0 0; color: var(--muted); font-size: 12px; }
.install-note { margin: 9px 0 0; color: var(--muted); font-size: 12.5px; }

.content-section { display: grid; grid-template-columns: minmax(220px, 0.52fr) minmax(0, 1.48fr); gap: clamp(48px, 8vw, 118px); padding: clamp(86px, 10vw, 124px) 0; border-top: 1px solid var(--line); }
.section-heading { align-self: start; }
.section-heading h2 { max-width: 360px; margin-top: 13px; font-size: clamp(27px, 2.7vw, 36px); line-height: 1.18; }
.section-count { margin: 16px 0 0; color: var(--muted); font-size: 13px; }
.section-body { min-width: 0; max-width: 760px; }
.section-body > :first-child { margin-top: 0; }
.section-body h3 { margin: 46px 0 14px; color: var(--ink); font-size: 20px; line-height: 1.35; }
.section-body p { margin: 18px 0; }
.section-body ul,
.section-body ol { margin: 16px 0; padding-left: 23px; }
.section-body li { margin: 7px 0; padding-left: 3px; }
.table-wrap { overflow-x: auto; margin: 0 0 30px; border-top: 1px solid var(--ink); }
table { width: 100%; border-collapse: collapse; font-size: 14px; line-height: 1.55; }
th,
td { border-bottom: 1px solid var(--line); padding: 15px 14px; text-align: left; vertical-align: top; }
th { color: var(--ink); background: var(--soft); font-size: 12px; font-weight: 600; }
td:first-child { width: 23%; }
.boundary-columns { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 42px; margin-top: 44px; }
.boundary-columns--single { grid-template-columns: minmax(0, 1fr); }
.boundary-columns h3 { margin-top: 0; }
.boundaries-section .section-body { font-family: var(--body); font-size: 14px; line-height: 1.65; }
.boundaries-section .section-body :is(table, th, h3) { font-family: inherit; font-size: inherit; line-height: inherit; }
.boundaries-section .section-body :is(h3, th, strong) { font-weight: 600; }
.product-design-tradeoffs li { margin: 22px 0; }
.product-design-tradeoffs li p { margin: 8px 0 0; }

.faq-list details { border-top: 1px solid var(--line); }
.faq-list details:last-child { border-bottom: 1px solid var(--line); }
.faq-list summary { position: relative; padding: 21px 44px 21px 0; color: var(--ink); font-weight: 600; line-height: 1.45; cursor: pointer; list-style: none; }
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary::after { position: absolute; top: 19px; right: 4px; color: var(--muted); content: "+"; font-family: var(--display); font-size: 21px; font-weight: 300; line-height: 1; }
.faq-list details[open] summary::after { content: "−"; }
.faq-list details > p,
.faq-answer { max-width: 680px; margin: 0; padding: 0 44px 22px 0; color: var(--muted); }
.faq-answer p:first-child { margin-top: 0; }
.faq-answer p:last-child { margin-bottom: 0; }
.faq-answer ul { margin-top: 10px; }
.faq-answer img { display: block; width: 100%; height: auto; margin: 14px 0 18px; border: 1px solid var(--line); border-radius: 12px; }
.feedback-section { color: #565960; }
.feedback-command { display: inline-block; padding: 0; color: var(--ink); background: transparent; font-family: var(--body); font-size: 1em; font-weight: 600; letter-spacing: 0; white-space: nowrap; }

.site-footer { display: flex; min-height: 110px; align-items: center; justify-content: space-between; gap: 22px; border-top: 1px solid var(--line); color: var(--muted); font-size: 13px; }
.footer-brand { color: var(--ink); font-family: var(--display); font-weight: 600; }
.footer-links { display: flex; gap: 22px; }
.footer-links a:hover { color: var(--ink); }

.legal-page { width: min(880px, calc(100% - 64px)); }
.legal-page .cover { padding: 96px 0 112px; border-bottom: 1px solid var(--line); }
.legal-page .cover-brand { display: flex; align-items: center; gap: 15px; }
.legal-page .cover h1 { margin: 0; color: var(--ink); font-family: var(--display); font-size: 34px; letter-spacing: -0.03em; }
.legal-page .cover > p { margin: 12px 0 0 67px; color: var(--muted); }
.legal-page .chapter { padding: 66px 0; border-bottom: 1px solid var(--line); }
.legal-page .chapter h2 { margin: 0 0 28px; color: var(--ink); font-family: var(--display); font-size: 26px; letter-spacing: -0.025em; }
.legal-page .chapter p,
.legal-page .chapter li { max-width: 760px; }
.legal-page footer { display: flex; align-items: center; justify-content: space-between; gap: 18px; padding: 32px 0 44px; color: var(--muted); font-size: 13px; }
.legal-page footer a:hover { color: var(--ink); }

@media (max-width: 1040px) {
  :root { --header-height: 86px; }
  .header-inner,
  main,
  .site-footer { width: min(100% - 44px, 900px); }
  .brand-logo { width: 46px; height: 46px; }
  .brand-name { font-size: 19px; }
  .brand-tagline { margin-top: 5px; font-size: 12.5px; }
  .site-nav { gap: 11px; font-size: 11.5px; }
  .hero { grid-template-columns: 1fr; gap: 44px; padding: 68px 0 84px; }
  .hero-copy { max-width: 720px; }
  .install-panel { max-width: 720px; }
}

@media (max-width: 760px) {
  :root { --header-height: 78px; }
  .header-inner,
  main,
  .site-footer { width: calc(100% - 36px); }
  .header-inner { min-height: var(--header-height); }
  .brand-logo { width: 42px; height: 42px; }
  .brand-name { font-size: 17px; }
  .brand-tagline { margin-top: 4px; font-size: 12px; }
  .nav-toggle { display: block; }
  .site-nav {
    position: absolute;
    top: 100%;
    right: 0;
    left: 0;
    display: none;
    align-items: stretch;
    flex-direction: column;
    gap: 0;
    border-bottom: 1px solid var(--line);
    padding: 8px 18px 14px;
    background: var(--white);
    font-size: 14px;
    white-space: normal;
  }
  .site-nav[data-open="true"] { display: flex; }
  .site-nav a { border-top: 1px solid var(--line); padding: 12px 2px; }
  .site-nav a:first-child { border-top: 0; }
  .site-nav a::after { display: none; }
  .hero { gap: 42px; padding: 56px 0 76px; }
  .hero h1 { font-size: clamp(28px, 8vw, 34px); }
  .install-panel { border-radius: 12px; padding: 25px 21px; box-shadow: none; }
  .button--primary { width: 100%; }
  .content-section { grid-template-columns: 1fr; gap: 38px; padding: 78px 0; }
  .section-heading h2 { font-size: 31px; }
  .table-wrap { width: calc(100vw - 36px); }
  table { min-width: 620px; }
  .boundary-columns { grid-template-columns: 1fr; gap: 32px; }
  .faq-list summary { padding-top: 18px; padding-bottom: 18px; }
  .faq-list summary::after { top: 16px; }
  .site-footer { align-items: flex-start; flex-direction: column; gap: 11px; padding: 30px 0; }
  .legal-page { width: calc(100% - 36px); }
  .legal-page .cover { padding: 70px 0 86px; }
  .legal-page .cover h1 { font-size: 28px; }
  .legal-page .cover > p { margin-left: 57px; }
  .legal-page .chapter { padding: 56px 0; }
  .legal-page footer { align-items: flex-start; flex-direction: column; gap: 10px; }
}

@media (max-width: 370px) {
  .brand-logo { width: 38px; height: 38px; }
  .brand-name { font-size: 15px; }
  .brand-tagline { font-size: 11px; }
  .nav-toggle-label { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .site-nav a::after { transition: none; }
}