:root {
  color-scheme: light;
  --c-bg: #F3F3F5;
  --c-panel: #FFFFFF;
  --c-panel-2: #E9E9EE;
  --c-line: #DCDDE3;
  --c-accent: #E01427;
  --c-accent-deep: #A50E1F;
  --c-accent-wash: #FDE8EA;
  --c-ink: #121318;
  --c-ink-soft: #5C5F6B;
  --c-ink-faint: #8B8E99;
  --c-white: #FFFFFF;
  --c-ok: #12A150;
  --c-ok-text: #096B35;
  --c-ok-wash: #E9F7EE;
  --c-ok-halo: rgba(18,161,80,.35);
  --c-warn: #C27A00;
  --c-warn-text: #805000;
  --c-warn-wash: #FFF3D9;
  --c-error: #C81E5B;
  --c-error-wash: #FCEAF1;
  --c-peach: #FFC9A8;
  --c-rose: #F7B6D2;
  --c-lilac: #D9C2F2;
  --c-sky: #A9D8F5;
  --c-aqua: #9EEBE3;
  --c-peach-wash: #FFF0E6;
  --c-rose-wash: #FCECF3;
  --c-lilac-wash: #F7F2FD;
  --c-aqua-wash: #EAF9F7;
  --c-peach-ink: #92512C;
  --c-lilac-ink: #75518D;
  --c-aqua-ink: #286C65;
  --c-rose-ink: #904467;
  --c-glass: rgba(255,255,255,.66);
  --c-glass-line: rgba(18,19,24,.08);
  --c-mask-solid: #000000;
  --c-mask-clear: rgba(0,0,0,0);
  --c-veil: rgba(18,19,24,.35);
  --c-win: #17181D;
  --c-win-bar: #1D1E24;
  --c-win-row: #1A1B21;
  --c-win-line: #2A2B33;
  --c-win-dot: #3B3D47;
  --c-win-text: #D3D5DD;
  --c-win-muted: #A3A6B1;
  --c-code-string: #9EEBE3;

  --f-display: "Inter","Noto Sans SC","PingFang SC","Microsoft YaHei",system-ui,sans-serif;
  --f-body: "Inter","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --f-mono: "JetBrains Mono",ui-monospace,"SFMono-Regular",Consolas,"Liberation Mono",monospace;
  --fs-xs: 12px;
  --fs-chip: 12.5px;
  --fs-sm: 13px;
  --fs-ui: 14px;
  --fs-nav: 15px;
  --fs-body: 16px;
  --fs-lede: 17px;
  --fs-sub: 18px;
  --fs-h3: 22px;
  --fs-h2: clamp(26px,3vw,38px);
  --fs-h1: clamp(34px,3.4vw,48px);
  --fw-normal: 400;
  --fw-medium: 500;
  --fw-semibold: 600;
  --fw-bold: 700;
  --fw-heavy: 800;
  --fw-display: 900;
  --lh-body: 1.6;
  --lh-title: 1.16;
  --ls-title: -.02em;
  --ls-ui: -.01em;

  --r-xs: 8px;
  --r-sm: 10px;
  --r-md: 16px;
  --r-card: 26px;
  --r-bar: 28px;
  --r-win: 32px;
  --r-frame: 40px;
  --r-pill: 999px;
  --r-circle: 50%;
  --sh-soft: 0 1px 2px rgba(18,19,24,.05),0 8px 24px -14px rgba(18,19,24,.18);
  --sh-btn: 0 10px 22px -10px rgba(224,20,39,.55),0 1px 2px rgba(165,14,31,.25);
  --sh-warm: 0 30px 70px -22px rgba(255,140,96,.48),0 10px 26px -12px rgba(247,150,180,.30),0 1px 2px rgba(18,19,24,.06);
  --sh-frame: 0 30px 60px -34px rgba(86,62,130,.40);
  --sh-win: 0 24px 48px -24px rgba(18,19,24,.55);
  --sh-float: 0 16px 40px rgba(18,19,24,.14);
  --nav-h: 64px;
  --wrap: 1200px;
  --reading: 820px;
  --header-wrap: 1280px;
  --gutter: 24px;
  --section-space: 88px;
  --ease: .2s ease;
  --reveal-time: .6s;
  --focus-width: 2px;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 24px; }
html, body { margin: 0; padding: 0; }
html.nav-open { overflow: hidden; }
body {
  background: var(--c-bg);
  color: var(--c-ink);
  font-family: var(--f-body);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
[hidden] { display: none !important; }
img, svg { max-width: 100%; vertical-align: middle; }
img { height: auto; }
button, input, select, textarea { font: inherit; }
button { cursor: pointer; }
button, a { -webkit-tap-highlight-color: var(--c-mask-clear); }
a { color: var(--c-accent); text-decoration-thickness: 1px; text-underline-offset: .2em; }
a:hover { color: var(--c-accent-deep); }
:focus-visible { outline: var(--focus-width) solid var(--c-accent); outline-offset: 3px; }
button:focus-visible, a:focus-visible { border-radius: var(--r-sm); }
h1, h2, h3 {
  font-family: var(--f-display);
  color: var(--c-ink);
  font-weight: var(--fw-display);
  letter-spacing: var(--ls-title);
  text-wrap: balance;
  overflow-wrap: normal;
}
h1 { font-size: var(--fs-h1); line-height: var(--lh-title); }
h2 { font-size: var(--fs-h2); line-height: 1.25; }
h3 { font-size: var(--fs-h3); line-height: 1.35; }
p { margin-block: 0 1em; }
code, pre, kbd { font-family: var(--f-mono); }
code { overflow-wrap: anywhere; }
pre {
  max-width: 100%;
  min-width: 0;
  overflow-x: auto;
  padding: 22px;
  border-radius: var(--r-md);
  background: var(--c-win);
  color: var(--c-win-text);
  font-size: var(--fs-ui);
}
pre code { white-space: pre; overflow-wrap: normal; word-break: normal; }
pre .code-string { color: var(--c-code-string); }
hr { border: 0; border-top: 1px solid var(--c-line); margin-block: 32px; }
.wrap { width: 100%; max-width: var(--wrap); margin-inline: auto; padding-inline: var(--gutter); }
.reading { width: 100%; max-width: var(--reading); margin-inline: auto; padding-inline: var(--gutter); }
.section { padding-top: var(--section-space); padding-bottom: var(--section-space); }
.section-title { margin-top: 0; margin-bottom: 24px; }
.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 > *, .feature-row > *, .footer-grid > *, .prose > *, .prose div { min-width: 0; }
.row { display: flex; align-items: center; flex-wrap: wrap; gap: 14px; }
.row > * { min-width: 0; }
.icon { width: 22px; height: 22px; flex-shrink: 0; }
.nowrap { white-space: nowrap; }
.muted { color: var(--c-ink-soft); }
.mono { font-family: var(--f-mono); }
.text-link { color: var(--c-accent); text-decoration: none; font-weight: var(--fw-bold); }
.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip-path: inset(50%); white-space: nowrap; border: 0;
}
.skip-link {
  position: fixed; left: var(--gutter); top: 8px; z-index: 100;
  transform: translateY(-160%); padding: 10px 16px;
  background: var(--c-panel); color: var(--c-accent); border-radius: var(--r-sm);
}
.skip-link:focus { transform: none; }
.prose { min-width: 0; }
.prose p, .prose li { line-height: 1.85; }
.prose h2 { margin-top: 2.2em; }
.prose h3 { margin-top: 1.6em; }
.prose :not(pre) > code {
  background: var(--c-panel-2); color: var(--c-ink);
  padding: .12em .3em; border-radius: var(--r-xs); font-size: .9em;
}
.prose ul, .prose ol { padding-left: 1.5em; }

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 9px;
  min-height: 50px; padding: 10px 26px;
  border: 1px solid var(--c-mask-clear); border-radius: var(--r-pill);
  font-family: var(--f-body); font-size: var(--fs-body); font-weight: var(--fw-bold);
  letter-spacing: var(--ls-ui); line-height: 1.4; text-decoration: none;
  transition: transform var(--ease),box-shadow var(--ease),background-color var(--ease),border-color var(--ease);
}
.btn svg { width: 18px; height: 18px; flex-shrink: 0; }
.btn--solid { background: var(--c-accent); color: var(--c-white); box-shadow: var(--sh-btn); }
.btn--solid:hover, .btn--solid.is-hover { background: var(--c-accent-deep); color: var(--c-white); transform: translateY(-1px); }
.btn--ghost { background: var(--c-panel); color: var(--c-ink); border-color: var(--c-line); box-shadow: var(--sh-soft); }
.btn--ghost:hover, .btn--ghost.is-hover { color: var(--c-ink); border-color: var(--c-ink-faint); transform: translateY(-1px); }
.btn:active, .btn.is-active { transform: translateY(1px); box-shadow: none; }
.btn:disabled, .btn[aria-disabled="true"] {
  background: var(--c-panel-2); color: var(--c-ink-soft);
  border-color: var(--c-line); box-shadow: none; cursor: not-allowed; transform: none;
}
.btn.is-focus { outline: var(--focus-width) solid var(--c-accent); outline-offset: 3px; }
.card, .panel {
  min-width: 0; padding: 28px;
  background: var(--c-panel); color: var(--c-ink);
  border: 1px solid var(--c-peach); border-radius: var(--r-card); box-shadow: var(--sh-soft);
}
.card h3 { margin-top: 0; }
.card--lilac { border-color: var(--c-lilac); }
.card--aqua { border-color: var(--c-aqua); }
.card--rose { border-color: var(--c-rose); }

.topbar { position: relative; z-index: 30; height: var(--nav-h); background: var(--c-panel); color: var(--c-ink); border-bottom: 1px solid var(--c-line); }
.topbar__inner {
  position: relative; max-width: min(100%,calc(var(--header-wrap) + var(--gutter) * 2));
  height: 100%; margin-inline: auto; padding-inline: var(--gutter);
  display: flex; align-items: center; gap: 32px;
}
.brand { display: inline-flex; align-items: center; gap: 11px; flex-shrink: 0; color: var(--c-ink); text-decoration: none; }
.brand:hover { color: var(--c-ink); }
.brand__mark { width: 34px; height: 34px; flex-shrink: 0; display: block; }
.brand__name { font-family: var(--f-display); font-weight: var(--fw-heavy); font-size: var(--fs-lede); letter-spacing: var(--ls-ui); }
.primary-nav { min-width: 0; margin-left: auto; }
.primary-nav__list { display: flex; align-items: center; gap: 30px; list-style: none; margin: 0; padding: 0; }
.primary-nav__list a {
  display: block; padding-block: 12px; white-space: nowrap; text-decoration: none;
  font-size: var(--fs-nav); font-weight: var(--fw-medium); color: var(--c-ink-soft);
  transition: color var(--ease);
}
.primary-nav__list a:hover { color: var(--c-ink); }
.primary-nav__list a[aria-current="page"], .mobile-nav a[aria-current="page"] { color: var(--c-accent); font-weight: var(--fw-bold); }
.header-tools { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }
.language { position: relative; }
.lang-switch {
  appearance: none; border: 1px solid var(--c-line); background: var(--c-panel); color: var(--c-ink);
  font-family: var(--f-body); font-size: var(--fs-ui); font-weight: var(--fw-medium);
  padding: 7px 14px; min-height: 38px; white-space: nowrap; border-radius: var(--r-pill);
}
.lang-switch:hover { border-color: var(--c-ink-faint); }
.lang-short { display: none; }
.language__menu {
  position: absolute; top: calc(100% + 10px); right: 0; width: 190px;
  margin: 0; padding: 8px; list-style: none;
  border: 1px solid var(--c-line); border-radius: var(--r-md);
  background: var(--c-panel); color: var(--c-ink); box-shadow: var(--sh-float);
}
.language__menu a { display: block; padding: 10px 12px; min-height: 44px; color: var(--c-ink-soft); text-decoration: none; border-radius: var(--r-sm); }
.language__menu a:hover { background: var(--c-bg); color: var(--c-accent); }
.language__menu a[aria-current="true"] { color: var(--c-accent); font-weight: var(--fw-bold); }
.menu-toggle {
  display: none; align-items: center; justify-content: center; min-width: 44px; min-height: 44px;
  border: 1px solid var(--c-line); border-radius: var(--r-sm);
  background: var(--c-panel); color: var(--c-ink);
}
.menu-toggle svg { width: 22px; height: 22px; }
.mobile-nav { display: none; }
.nav-veil { position: fixed; inset: var(--nav-h) 0 0; z-index: 20; background: var(--c-veil); color: var(--c-ink); border: 0; }

.site-footer { border-top: 1px solid var(--c-line); padding-top: 56px; padding-bottom: 28px; background: var(--c-panel); color: var(--c-ink); }
.footer-grid { display: grid; grid-template-columns: 1.25fr .8fr 1.4fr .65fr; gap: 36px; }
.footer-grid h2 { font-size: var(--fs-nav); font-weight: var(--fw-bold); margin-top: 0; margin-bottom: 16px; letter-spacing: normal; }
.footer-brand p { color: var(--c-ink-soft); font-size: var(--fs-ui); margin-top: 18px; max-width: 30em; }
.footer-list { list-style: none; margin: 0; padding: 0; }
.footer-list a { display: inline-block; padding-block: 6px; color: var(--c-ink-soft); text-decoration: none; font-size: var(--fs-ui); overflow-wrap: anywhere; }
.footer-list a:hover { color: var(--c-accent); }
.footer-bottom { margin-top: 40px; padding-top: 20px; border-top: 1px solid var(--c-line); display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px; font-size: var(--fs-sm); color: var(--c-ink-soft); }
.footer-bottom p { margin: 0; }
.footer-bottom a { color: var(--c-accent); }

.reveal { opacity: 1; transform: none; }
.reveal-pending .reveal:not(.shown) { opacity: 0; transform: translateY(18px); }
.reveal-pending .reveal { transition: opacity var(--reveal-time) ease,transform var(--reveal-time) ease; }
.reveal.shown { opacity: 1; transform: none; }

@media (max-width: 1280px) {
  .topbar__inner { gap: 20px; }
  .primary-nav__list { gap: 20px; }
  .primary-nav__list a { font-size: var(--fs-ui); }
}
@media (max-width: 1100px) {
  .primary-nav { display: none; }
  .header-tools { margin-left: auto; }
  .menu-toggle { display: inline-flex; }
  .mobile-nav:not([hidden]) {
    display: block; position: absolute; top: var(--nav-h); left: 0; right: 0; z-index: 2;
    max-height: calc(100dvh - var(--nav-h)); overflow-y: auto; overscroll-behavior: contain;
    padding: 16px var(--gutter) 24px; background: var(--c-panel); color: var(--c-ink);
    border-bottom: 1px solid var(--c-line); box-shadow: var(--sh-soft);
  }
  .mobile-nav ul { list-style: none; margin: 0; padding: 0; }
  .mobile-nav a { display: flex; align-items: center; width: 100%; min-height: 46px; padding: 11px 12px; color: var(--c-ink-soft); text-decoration: none; border-radius: var(--r-sm); }
  .mobile-nav a:hover { background: var(--c-bg); color: var(--c-accent); }
  .mobile-nav__languages { margin-top: 16px; padding-top: 16px; border-top: 1px solid var(--c-line); }
  .footer-grid { grid-template-columns: repeat(2,minmax(0,1fr)); }
}
@media (max-width: 768px) {
  :root { --fs-h1: clamp(24px,4vw,30px); --section-space: 56px; }
  .grid--three { grid-template-columns: minmax(0,1fr); }
}
@media (max-width: 640px) {
  :root { --gutter: 16px; }
  .grid--two, .footer-grid { grid-template-columns: minmax(0,1fr); }
  .topbar__inner { gap: 10px; }
  .brand { gap: 7px; }
  .brand__name { font-size: var(--fs-ui); }
  .brand__mark { width: 30px; height: 30px; }
  .header-tools { margin-left: auto; gap: 6px; }
  .lang-full { display: none; }
  .lang-short { display: inline; }
  .lang-switch { padding-inline: 10px; }
  .card, .panel { padding: 22px; }
  .tilt, [data-tilt] { transform: none !important; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .reveal-pending .reveal:not(.shown) { opacity: 1; transform: none; }
}
@media print {
  .header-tools, .mobile-nav, .nav-veil { display: none !important; }
  .reveal-pending .reveal:not(.shown) { opacity: 1; transform: none; }
}