:root {
  --ground: #F7F8F4;
  --tray: #F1F2ED;
  --tray-2: #EAEBE6;
  --hairline: #E1E2DC;
  --paper: #FBFBF8;
  --paper-hi: #FFFFFF;
  --ink: #23231F;
  --ink-hover: #3A3A35;
  --ink-soft: #6E6E68;
  --ink-faint: #9C9C95;
  --ink-on-dark: #F7F8F4;
  --amber: #C27C2C;
  --amber-deep: #9A5F1C;
  --ok: #4F8A5B;
  --ok-halo: rgba(79,138,91,.45);
  --warn: #B8892A;
  --err: #B5483B;
  --ctl-line: #CBCCC5;
  --switch-off: #D7D8D1;
  --chrome-dot: #D3D4CD;
  --chrome-dot-edge: rgba(35,35,31,.10);
  --bezel-hi: #EEEFEA;
  --bezel-lo: #D9DAD3;
  --paint-sky: #CFCCD3;
  --paint-haze: #D7D7CE;
  --paint-shore: #C2C6BB;
  --paint-water: #A6AFB5;
  --paint-edge: rgba(35,35,31,.06);
  --paint-dusk-a: rgba(178,168,190,.60);
  --paint-lime-a: rgba(218,220,200,.75);
  --paint-sage-a: rgba(138,152,126,.55);
  --paint-slate-a: rgba(128,143,158,.55);
  --paint-ridge-a: rgba(148,158,148,.50);
  --paint-water-a: rgba(116,131,146,.60);
  --paint-glint-a: rgba(236,237,228,.55);
  --paint-glint-b: rgba(214,220,222,.50);
  --paint-shade-a: rgba(86,96,104,.22);
  --paint-cloud-a: rgba(232,229,236,.55);
  --paint-mount-a: rgba(122,134,140,.42);
  --paint-mount-b: rgba(146,140,160,.38);
  --paint-light-a: rgba(247,248,244,.35);
  --clear: transparent;
  --r-ctl: 4px;
  --r-row: 6px;
  --r-card: 8px;
  --r-window: 10px;
  --r-stage: 12px;
  --r-phone: 30px;
  --r-screen: 23px;
  --r-pill: 999px;
  --r-round: 50%;
  --lift-window: 0 0 0 1px rgba(35,35,31,.02), 0 2px 5px rgba(35,35,31,.06), 0 24px 52px -20px rgba(35,35,31,.32);
  --lift-phone: 0 3px 6px rgba(35,35,31,.10), 0 18px 36px -10px rgba(35,35,31,.26), 0 46px 84px -24px rgba(35,35,31,.44);
  --lift-pop: 0 1px 2px rgba(35,35,31,.06), 0 12px 30px -10px rgba(35,35,31,.22);
  --lift-knob: 0 1px 2px rgba(35,35,31,.24);
  --lift-seg: 0 1px 2px rgba(35,35,31,.14);
  --lift-fab: 0 2px 4px rgba(35,35,31,.18), 0 8px 16px -6px rgba(35,35,31,.30);
  --bezel-inset: inset 0 1px 0 rgba(255,255,255,.75), inset 0 0 0 1px rgba(35,35,31,.07);
  --font-display: "Inter", "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --font-body: "Inter", "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  --weight-normal: 400;
  --weight-medium: 500;
  --text-xs: 12px;
  --text-sm: 14px;
  --text-base: 15px;
  --text-lg: 18px;
  --text-h3: 22px;
  --text-h2: clamp(24px, 2.5vw, 32px);
  --text-h1: clamp(34px, 3.2vw, 46px);
  --leading-body: 1.6;
  --leading-title: 1.16;
  --tracking-title: -.012em;
  --gutter: 32px;
  --content-width: 1240px;
  --reading-width: 780px;
  --header-width: 1280px;
  --header-height: 64px;
  --space-section: 96px;
  --motion-short: 160ms;
  --motion-reveal: 650ms;
  --ease-out: cubic-bezier(.2,.7,.2,1);
}
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 24px; }
html.nav-open { overflow: hidden; }
body {
  margin: 0;
  background: var(--ground);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-normal);
  line-height: var(--leading-body);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
a { color: var(--amber-deep); text-decoration-thickness: 1px; text-underline-offset: .2em; }
a:hover { color: var(--ink); }
button, input, select, textarea { font: inherit; }
button, summary { -webkit-tap-highlight-color: var(--clear); }
button { cursor: pointer; }
button:disabled { cursor: not-allowed; }
img, svg { display: block; max-width: 100%; }
img { height: auto; }
svg, .icon, .pulse-dot { flex-shrink: 0; }
button svg, a svg { pointer-events: none; }
figure { margin: 0; }
p { margin: 0 0 1em; }
h1, h2, h3, h4 {
  margin: 0 0 .65em;
  font-family: var(--font-display);
  font-weight: var(--weight-normal);
  text-wrap: balance;
}
h1 { font-size: var(--text-h1); line-height: var(--leading-title); letter-spacing: var(--tracking-title); }
h2 { font-size: var(--text-h2); line-height: 1.25; letter-spacing: -.005em; }
h3 { font-size: var(--text-h3); line-height: 1.35; }
h4 { font-size: var(--text-lg); }
strong, b { font-weight: var(--weight-medium); }
small { font-size: var(--text-xs); }
hr { margin-block: 32px; border: 0; border-top: 1px solid var(--hairline); }
:focus-visible { outline: 2px solid var(--amber); outline-offset: 3px; border-radius: var(--r-ctl); }
[hidden] { display: none !important; }
.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}
.skip-link {
  position: absolute; z-index: 100; top: 8px; left: 16px;
  width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0);
  white-space: nowrap;
  padding: 0; background: var(--ink); color: var(--ink-on-dark);
  border-radius: var(--r-ctl);
}
.skip-link:focus {
  width: auto; height: auto; overflow: visible; clip: auto;
  white-space: normal; padding: 10px 16px; color: var(--ink-on-dark);
}
.wrap, .frame {
  width: 100%; max-width: calc(var(--content-width) + var(--gutter) * 2);
  margin-inline: auto; padding-inline: var(--gutter);
}
.reading { max-width: calc(var(--reading-width) + var(--gutter) * 2); }
.section { padding-top: var(--space-section); padding-bottom: var(--space-section); }
.section-head { max-width: 680px; margin-bottom: 32px; }
.section-head p, .muted { color: var(--ink-soft); }
.keep { white-space: nowrap; }
.grid { display: grid; gap: 24px; }
.grid-two { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-three { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid > *, .lead > *, .feature-tabs > *, .footer-grid > *, .split-row > * { min-width: 0; }
.cluster { display: flex; align-items: center; flex-wrap: wrap; gap: 12px; }
.stack > * + * { margin-top: 20px; }
.prose, .article-body { min-width: 0; line-height: 1.85; }
.prose h2, .article-body h2 { margin-top: 2.2em; scroll-margin-top: 24px; }
.prose h3, .article-body h3 { margin-top: 1.6em; }
.prose li + li, .article-body li + li { margin-top: .45em; }
.prose img, .article-body img { border-radius: var(--r-card); }
code { font-family: var(--font-mono); font-size: .88em; overflow-wrap: anywhere; }
:not(pre) > code {
  padding: 2px 5px; border-radius: var(--r-ctl);
  background: var(--tray-2); color: var(--ink);
}
pre {
  min-width: 0; max-width: 100%; overflow-x: auto; overscroll-behavior-x: contain;
  padding: 20px; border: 1px solid var(--hairline); border-radius: var(--r-card);
  background: var(--tray); color: var(--ink); line-height: 1.65;
}
pre code { white-space: pre; overflow-wrap: normal; word-break: normal; }
.btn-solid, .btn-soft, .pill-line, .button {
  display: inline-flex; align-items: center; justify-content: center; gap: 9px;
  max-width: 100%; min-height: 46px; padding: 10px 22px;
  border: 1px solid var(--clear); border-radius: var(--r-pill);
  font-size: var(--text-base); line-height: 1.3; text-decoration: none;
  transition: background var(--motion-short), border-color var(--motion-short);
}
.btn-solid, .button { background: var(--ink); color: var(--ink-on-dark); }
.btn-solid:hover, .button:hover, .btn-solid.is-hover { background: var(--ink-hover); color: var(--ink-on-dark); }
.btn-soft { background: var(--tray-2); color: var(--ink); border-color: var(--hairline); }
.btn-soft:hover, .btn-soft.is-hover { background: var(--hairline); color: var(--ink); }
.pill-line {
  min-height: 36px; padding: 7px 16px; font-size: var(--text-sm);
  background: var(--ground); color: var(--ink); border-color: var(--hairline);
}
.pill-line:hover { background: var(--tray); color: var(--ink); }
.btn-solid:disabled, .btn-soft:disabled, .button:disabled {
  background: var(--tray-2); color: var(--ink-soft); border-color: var(--ctl-line);
}
.is-focus { outline: 2px solid var(--amber); outline-offset: 3px; }
.btn-ico { width: 15px; height: 15px; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.text-link { display: inline-flex; align-items: center; gap: 6px; color: var(--amber-deep); text-decoration: none; }
.text-link:hover { color: var(--ink); text-decoration: underline; }
.card, .panel {
  padding: 28px; border: 1px solid var(--hairline); border-radius: var(--r-card);
  background: var(--paper); color: var(--ink); box-shadow: var(--lift-pop);
}
.panel { background: var(--tray); color: var(--ink); box-shadow: none; }
.card p:last-child, .panel p:last-child { margin-bottom: 0; }
.split-row {
  display: grid; grid-template-columns: minmax(0, .8fr) minmax(0, 1.2fr);
  align-items: center; gap: 56px; padding: 36px;
  background: var(--tray); color: var(--ink); border-radius: var(--r-stage);
}
.split-row.is-reversed { grid-template-columns: minmax(0, 1.2fr) minmax(0, .8fr); }
.split-row.is-reversed .split-copy { order: 2; }
.topbar, #site-header { position: relative; z-index: 30; background: var(--ground); color: var(--ink); }
.topbar-in {
  width: 100%; max-width: min(100%, calc(var(--header-width) + var(--gutter) * 2));
  margin-inline: auto; padding-inline: var(--gutter);
  height: var(--header-height); display: flex; align-items: center; gap: 32px;
}
.brand { display: inline-flex; align-items: center; gap: 10px; flex-shrink: 0; color: var(--ink); text-decoration: none; }
.brand-mark { width: 26px; height: 26px; flex-shrink: 0; }
.brand-name { font-size: var(--text-base); font-weight: var(--weight-medium); letter-spacing: .01em; }
.mainnav { flex: 1; min-width: 0; display: flex; justify-content: center; }
.navline { display: flex; align-items: center; list-style: none; margin: 0; padding: 0; gap: 2px; }
.navline > li { flex-shrink: 0; }
.navline a, .navmore summary {
  display: inline-flex; align-items: center; gap: 5px; padding: 7px 13px;
  border-radius: var(--r-pill); font-size: var(--text-sm);
  color: var(--ink-soft); text-decoration: none; cursor: pointer;
}
.navline a:hover, .navmore summary:hover, .navline a[aria-current="page"], .navmore.is-current summary { color: var(--ink); }
.navmore, .langpick { position: relative; }
.navmore summary, .langpick summary { list-style: none; }
.navmore summary::-webkit-details-marker, .langpick summary::-webkit-details-marker { display: none; }
.chev { width: 10px; height: 10px; fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
.drop {
  position: absolute; top: calc(100% + 8px); left: 0; z-index: 5; min-width: 180px;
  padding: 6px; background: var(--paper-hi); color: var(--ink);
  border: 1px solid var(--hairline); border-radius: var(--r-card); box-shadow: var(--lift-pop);
}
.drop a { display: flex; align-items: center; min-height: 44px; padding: 9px 10px; border-radius: var(--r-row); font-size: var(--text-sm); color: var(--ink-soft); text-decoration: none; }
.drop a:hover, .drop a[aria-current] { background: var(--tray); color: var(--ink); }
.drop-right { left: auto; right: 0; }
.topbar-tools { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }
.langpick summary {
  display: inline-flex; align-items: center; gap: 6px; cursor: pointer;
  min-height: 44px; padding: 7px 10px; font-size: var(--text-sm);
  color: var(--ink-soft); border-radius: var(--r-pill);
}
.globe { width: 15px; height: 15px; fill: none; stroke: currentColor; stroke-width: 1.4; }
.lang-short { display: none; }
.menu-toggle {
  display: none; align-items: center; justify-content: center;
  min-width: 44px; min-height: 44px; padding: 10px;
  background: var(--ground); color: var(--ink); border: 1px solid var(--hairline); border-radius: var(--r-ctl);
}
.menu-toggle svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.5; }
.mobile-drawer { display: none; }
.nav-veil { position: fixed; inset: var(--header-height) 0 0; z-index: 25; background: var(--paint-shade-a); color: var(--ink); }
.site-footer {
  margin-top: 64px; padding-top: 56px; padding-bottom: 104px;
  border-top: 1px solid var(--hairline); background: var(--tray); color: var(--ink);
}
.footer-grid { display: grid; grid-template-columns: 1.2fr 1fr 1.3fr .8fr; gap: 40px; }
.footer-brand p { max-width: 280px; margin-top: 18px; font-size: var(--text-sm); color: var(--ink-soft); }
.footer-title { font-size: var(--text-sm); font-weight: var(--weight-medium); margin-bottom: 14px; }
.footer-links { display: grid; gap: 10px; list-style: none; margin: 0; padding: 0; }
.footer-links a { color: var(--ink-soft); text-decoration: none; font-size: var(--text-sm); overflow-wrap: anywhere; }
.footer-links a:hover { color: var(--amber-deep); }
.footer-bottom { margin-top: 40px; padding-top: 20px; border-top: 1px solid var(--hairline); font-size: var(--text-xs); color: var(--ink-soft); }
.reveal { opacity: 1; transform: none; }
.reveal.is-pending { opacity: 0; transform: translateY(16px); transition: opacity var(--motion-reveal) var(--ease-out), transform var(--motion-reveal) var(--ease-out); }
.reveal.shown { opacity: 1; transform: none; }
.decorated, .hero { overflow-x: clip; }
@media (max-width: 1100px) {
  .topbar-in { gap: 20px; }
  .mainnav { display: none; }
  .topbar-tools { margin-left: auto; }
  .menu-toggle { display: inline-flex; }
  .mobile-drawer:not([hidden]) {
    display: block; position: absolute; top: var(--header-height); left: 0; right: 0;
    max-height: calc(100dvh - var(--header-height)); overflow-y: auto; overscroll-behavior: contain;
    padding: 16px var(--gutter) 24px; background: var(--ground); color: var(--ink);
    border-bottom: 1px solid var(--hairline); box-shadow: var(--lift-pop);
  }
  .mobile-drawer ul { list-style: none; margin: 0; padding: 0; }
  .mobile-drawer a { display: flex; align-items: center; width: 100%; min-height: 44px; padding: 11px 12px; border-radius: var(--r-ctl); color: var(--ink); text-decoration: none; }
  .mobile-drawer a:hover, .mobile-drawer a[aria-current] { background: var(--tray-2); color: var(--ink); }
  .drawer-label { padding: 18px 12px 8px; margin: 12px 0 0; border-top: 1px solid var(--hairline); color: var(--ink-soft); font-size: var(--text-xs); }
  .footer-grid { grid-template-columns: repeat(2, minmax(0,1fr)); }
}
@media (max-width: 768px) {
  :root { --text-h1: clamp(24px, 4vw, 30px); --space-section: 64px; }
  .grid-three { grid-template-columns: 1fr; }
  .split-row, .split-row.is-reversed { grid-template-columns: 1fr; gap: 28px; padding: 24px; }
  .split-row.is-reversed .split-copy { order: initial; }
}
@media (max-width: 640px) {
  :root { --gutter: 16px; }
  .topbar-in { gap: 12px; }
  .topbar-tools { margin-left: auto; gap: 4px; }
  .topbar-tools > .pill-line { display: none; }
  .brand-name { font-size: var(--text-sm); }
  .lang-full { display: none; }
  .lang-short { display: inline; }
  .grid-two, .footer-grid { grid-template-columns: 1fr; }
  .card, .panel { padding: 20px; }
  .tilt, [data-tilt] { transform: none !important; }
  .footer-grid { gap: 28px; }
  .section-head { margin-bottom: 24px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal.is-pending { opacity: 1; transform: none; transition: none; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}