:root {
  --c-bg: #f3f3f5;
  --c-panel: #ffffff;
  --c-panel-2: #e9e9ee;
  --c-border: #dcdce3;
  --c-accent: #e5590f;
  --c-accent-dark: #b8430a;
  --c-signal: #2a5cf0;
  --c-text: #111217;
  --c-muted: #5c5f6b;
  --c-faint: #8d909b;
  --c-comma: #b3b5bf;
  --c-success: #1f9d62;
  --c-warn: #c98a05;
  --c-error: #d6304a;
  --c-on-accent: #ffffff;
  --c-peach: #f4b896;
  --c-lilac: #d9b3ea;
  --c-sky: #9fd3f2;
  --c-field-peach: #f7c4a5;
  --c-field-lilac: #e3b9ec;
  --c-field-sky: #a9dcf5;
  --c-peach-soft: #fdf0e8;
  --c-lilac-soft: #f6eefa;
  --c-sky-soft: #e7f4fc;
  --c-glass: rgba(255, 255, 255, 0.6);
  --c-glass-strong: rgba(255, 255, 255, 0.78);
  --c-glass-line: rgba(255, 255, 255, 0.92);
  --c-hl: rgba(229, 89, 15, 0.22);
  --c-accent-ring: rgba(229, 89, 15, 0.16);
  --c-mask: #000000;
  --c-clear: rgba(255, 255, 255, 0);
  --c-code-bg: #15161b;
  --c-code-text: #f3f3f5;
  --c-code-type: #9bb8ff;
  --c-code-policy: #ffae82;
  --c-veil: rgba(17, 18, 23, 0.24);

  --shadow-card: 0 12px 32px rgba(17, 18, 23, 0.06);
  --shadow-soft: 0 1px 2px rgba(17, 18, 23, 0.05), 0 4px 12px rgba(17, 18, 23, 0.04);
  --shadow-bar: 0 1px 2px rgba(17, 18, 23, 0.05), 0 8px 18px rgba(229, 89, 15, 0.08), 0 24px 60px rgba(229, 89, 15, 0.14);
  --shadow-btn: 0 1px 1px rgba(184, 67, 10, 0.3), 0 10px 24px rgba(229, 89, 15, 0.26);
  --shadow-menu: 0 18px 44px rgba(17, 18, 23, 0.1);

  --font-display: "Inter", "Noto Sans SC", -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "Inter", "Noto Sans SC", -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --weight-normal: 400;
  --weight-medium: 500;
  --weight-semibold: 650;
  --weight-bold: 700;
  --weight-display: 800;
  --text-xs: 12px;
  --text-sm: 13px;
  --text-label: 14px;
  --text-nav: 15px;
  --text-body: 16px;
  --text-lead: 17px;
  --text-h3: 22px;
  --text-h2: clamp(24px, 2.3vw, 32px);
  --text-h1: clamp(34px, 3.4vw, 48px);
  --tracking-title: -0.02em;
  --tracking-brand: -0.02em;
  --tracking-label: 0.04em;
  --line-body: 1.6;
  --line-prose: 1.85;

  --r-card: 28px;
  --r-bar: 20px;
  --r-btn: 16px;
  --r-menu: 18px;
  --r-code: 14px;
  --r-md: 12px;
  --r-sm: 10px;
  --r-shot: 10px;
  --r-mobile-card: 22px;
  --r-highlight: 5px;
  --r-bracket: 3px;
  --r-pill: 999px;
  --r-circle: 50%;

  --wrap: 1280px;
  --header-content: 1280px;
  --reading: 780px;
  --gutter: 48px;
  --head-h: 68px;
  --section-gap: 140px;
  --card-pad: 28px;
  --code-size: clamp(14px, 1.55vw, 22px);
  --drop: 24px;
  --shot-width: 280px;
  --stroke: 1px;
  --focus-width: 2px;
  --focus-offset: 3px;
  --ease: ease;
  --duration-fast: 0.18s;
  --duration: 0.2s;
  --duration-reveal: 0.55s;
  --duration-glow: 28s;
  --blur-field: 46px;
  --blur-glass: 16px;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: calc(var(--head-h) + 24px); }
html.nav-open { overflow: hidden; }
body {
  margin: 0;
  background: var(--c-bg);
  color: var(--c-text);
  font: var(--weight-normal) var(--text-body)/var(--line-body) var(--font-body);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
[hidden] { display: none !important; }
img, svg { max-width: 100%; }
img { height: auto; }
button, input, select, textarea { font: inherit; }
button { cursor: pointer; }
button, a { -webkit-tap-highlight-color: var(--c-clear); }
button:disabled { cursor: not-allowed; }
a { color: var(--c-signal); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 0.2em; }
:focus-visible { outline: var(--focus-width) solid var(--c-signal); outline-offset: var(--focus-offset); border-radius: var(--r-sm); }
::selection { background: var(--c-sky-soft); color: var(--c-text); }
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: var(--weight-display);
  letter-spacing: var(--tracking-title);
  text-wrap: balance;
  overflow-wrap: break-word;
}
h1 { font-size: var(--text-h1); line-height: 1.16; }
h2 { font-size: var(--text-h2); line-height: 1.25; }
h3 { font-size: var(--text-h3); line-height: 1.35; }
p { margin-top: 0; }
code, pre, kbd { font-family: var(--font-mono); }
code { overflow-wrap: anywhere; }
pre {
  max-width: 100%;
  min-width: 0;
  overflow-x: auto;
  padding: 24px;
  border-radius: var(--r-code);
  background: var(--c-code-bg);
  color: var(--c-code-text);
  font-size: var(--text-label);
  line-height: 1.9;
  tab-size: 2;
}
pre code { overflow-wrap: normal; word-break: normal; white-space: pre; }
svg { vertical-align: middle; flex-shrink: 0; }
:where(main, section, article, aside, div, li, figure) { min-width: 0; }
.wrap { width: 100%; max-width: var(--wrap); margin-inline: auto; padding-inline: var(--gutter); }
.reading { max-width: var(--reading); margin-inline: auto; }
.section { padding-top: var(--section-gap); padding-bottom: 0; }
.section:last-child { padding-bottom: var(--section-gap); }
.section-heading { margin-bottom: 32px; }
.section-heading h2 { margin: 0; }
.section-heading p { max-width: 42em; margin-top: 14px; color: var(--c-muted); }
.prose { line-height: var(--line-prose); }
.prose h2 { margin-top: 64px; scroll-margin-top: calc(var(--head-h) + 24px); }
.prose h3 { margin-top: 36px; }
.prose p, .prose ul, .prose ol { margin-bottom: 24px; }
.prose li + li { margin-top: 8px; }
.prose img { max-width: 100%; }
.prose > :first-child { margin-top: 0; }
.muted { color: var(--c-muted); }
.keep { white-space: nowrap; }
.mono { font-family: var(--font-mono); }
.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: fixed; top: 8px; left: 16px; z-index: 100; transform: translateY(-160%); padding: 10px 16px; background: var(--c-panel); color: var(--c-signal); border-radius: var(--r-sm); }
.skip-link:focus { transform: none; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 54px;
  max-width: 100%;
  padding: 12px 24px;
  border: var(--stroke) solid var(--c-clear);
  border-radius: var(--r-btn);
  font: var(--weight-bold) var(--text-body)/1.35 var(--font-body);
  text-align: center;
  transition: background-color var(--duration) var(--ease), transform var(--duration) var(--ease), border-color var(--duration) var(--ease);
}
.btn svg { width: 19px; height: 19px; }
.btn:hover { text-decoration: none; }
.btn-primary { padding-left: 20px; background: var(--c-accent); color: var(--c-on-accent); box-shadow: var(--shadow-btn); }
.btn-primary:hover, .btn-primary.is-hover { background: var(--c-accent-dark); color: var(--c-on-accent); transform: translateY(-1px); }
.btn-primary:active { transform: translateY(0); }
.btn-ghost { background: var(--c-panel); color: var(--c-text); border-color: var(--c-border); box-shadow: var(--shadow-soft); }
.btn-ghost:hover { border-color: var(--c-faint); transform: translateY(-1px); }
.btn-ghost svg { width: 16px; height: 16px; color: var(--c-muted); }
.btn:disabled, .btn[aria-disabled="true"] { background: var(--c-panel-2); color: var(--c-muted); border-color: var(--c-border); box-shadow: none; transform: none; }
.btn.is-focus { outline: var(--focus-width) solid var(--c-signal); outline-offset: var(--focus-offset); }

#site-header, .masthead { position: sticky; top: 0; z-index: 30; background: var(--c-panel); color: var(--c-text); border-bottom: var(--stroke) solid var(--c-border); }
.header-wrap { width: 100%; max-width: min(100%, calc(var(--header-content) + var(--gutter) * 2)); padding-inline: var(--gutter); margin-inline: auto; }
.masthead-row { height: var(--head-h); display: flex; align-items: center; gap: 24px; }
.brand { display: inline-flex; align-items: center; gap: 11px; color: var(--c-text); font: var(--weight-display) var(--text-lead)/1.3 var(--font-display); letter-spacing: var(--tracking-brand); margin-right: auto; flex-shrink: 0; }
.brand:hover { text-decoration: none; }
.brand-mark { display: block; width: 34px; height: 34px; flex-shrink: 0; border-radius: var(--r-circle); }
.brand-sub { font: var(--weight-semibold) var(--text-sm)/1.3 var(--font-body); letter-spacing: 0; color: var(--c-muted); padding-left: 10px; border-left: var(--stroke) solid var(--c-border); }
.desktop-nav { min-width: 0; }
.nav-main { display: flex; align-items: center; gap: 2px; list-style: none; margin: 0; padding: 0; }
.nav-main > li { position: relative; flex-shrink: 0; }
.nav-link, .nav-more-btn {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  min-height: 38px;
  padding: 8px 14px;
  border-radius: var(--r-sm);
  color: var(--c-muted);
  font: var(--weight-medium) var(--text-nav)/1.3 var(--font-body);
  background: var(--c-clear);
  border: 0;
  white-space: nowrap;
  transition: color var(--duration-fast) var(--ease), background-color var(--duration-fast) var(--ease);
}
.nav-link:hover, .nav-more-btn:hover, .nav-more-btn[aria-expanded="true"] { color: var(--c-text); background: var(--c-bg); text-decoration: none; }
.nav-link[aria-current="page"], .nav-menu a[aria-current="page"] { color: var(--c-text); font-weight: var(--weight-semibold); background: var(--c-bg); }
.chev { width: 14px; height: 14px; transition: transform var(--duration-fast) var(--ease); }
[aria-expanded="true"] > .chev, details[open] > summary .chev { transform: rotate(180deg); }
.nav-menu {
  position: absolute;
  top: calc(100% + 10px);
  right: 0;
  min-width: 236px;
  max-width: calc(100vw - 32px);
  margin: 0;
  padding: 8px;
  list-style: none;
  background: var(--c-panel);
  color: var(--c-text);
  border: var(--stroke) solid var(--c-border);
  border-radius: var(--r-menu);
  box-shadow: var(--shadow-menu);
  z-index: 65;
}
.nav-menu-group { padding: 6px 12px 4px; font-size: var(--text-xs); font-weight: var(--weight-semibold); color: var(--c-muted); }
.nav-menu a { display: block; min-height: 44px; padding: 10px 12px; border-radius: var(--r-md); color: var(--c-text); font-size: var(--text-nav); font-weight: var(--weight-semibold); line-height: 1.35; }
.nav-menu a span { display: block; margin-top: 2px; font-size: var(--text-sm); font-weight: var(--weight-normal); color: var(--c-muted); }
.nav-menu a:hover { background: var(--c-bg); color: var(--c-text); text-decoration: none; }
.header-tools { display: flex; align-items: center; gap: 8px; flex-shrink: 0; }
.language-picker { position: relative; }
.lang { display: inline-flex; align-items: center; justify-content: center; gap: 7px; min-height: 38px; padding: 8px 12px 8px 14px; margin-left: 6px; border: var(--stroke) solid var(--c-border); border-radius: var(--r-pill); background: var(--c-panel); color: var(--c-text); font: var(--weight-medium) var(--text-label)/1.3 var(--font-body); white-space: nowrap; }
.lang .globe { width: 16px; height: 16px; color: var(--c-muted); }
.lang-short { display: none; }
.menu-toggle { display: none; align-items: center; justify-content: center; min-width: 44px; min-height: 44px; border: var(--stroke) solid var(--c-border); border-radius: var(--r-sm); background: var(--c-panel); color: var(--c-text); }
.menu-toggle svg { width: 22px; height: 22px; }
.nav-veil { position: fixed; inset: var(--head-h) 0 0; z-index: 40; border: 0; background: var(--c-veil); color: var(--c-text); }
.mobile-drawer { position: absolute; inset: var(--head-h) 0 auto; z-index: 50; max-height: calc(100dvh - var(--head-h)); overflow-y: auto; overscroll-behavior: contain; background: var(--c-panel); color: var(--c-text); border-bottom: var(--stroke) solid var(--c-border); box-shadow: var(--shadow-menu); padding: 16px var(--gutter) 24px; }
.mobile-drawer ul { list-style: none; margin: 0; padding: 0; }
.mobile-drawer a { display: flex; align-items: center; width: 100%; min-height: 48px; padding: 12px 16px; color: var(--c-text); border-radius: var(--r-md); }
.mobile-drawer a:hover, .mobile-drawer a[aria-current="page"] { background: var(--c-bg); color: var(--c-text); text-decoration: none; }
.drawer-label { margin: 16px 16px 4px; color: var(--c-muted); font-size: var(--text-sm); }
.preview-dropdown { position: relative; }
.preview-dropdown > summary { list-style: none; cursor: pointer; }
.preview-dropdown > summary::-webkit-details-marker { display: none; }

.card, .panel { padding: var(--card-pad); background: var(--c-panel); color: var(--c-text); border: var(--stroke) solid var(--c-peach); border-radius: var(--r-card); box-shadow: var(--shadow-card); }
.card h3, .panel h3 { margin-top: 0; }
.card p:last-child, .panel p:last-child { margin-bottom: 0; }
.tone-peach { --panel-line: var(--c-peach); --panel-fill: var(--c-peach-soft); }
.tone-lilac { --panel-line: var(--c-lilac); --panel-fill: var(--c-lilac-soft); }
.tone-sky { --panel-line: var(--c-sky); --panel-fill: var(--c-sky-soft); }
.card.tone-lilac, .panel.tone-lilac { border-color: var(--c-lilac); }
.card.tone-sky, .panel.tone-sky { border-color: var(--c-sky); }
.card-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 24px; }
.card-grid > * { min-width: 0; }
.kicker { display: inline-flex; align-items: center; gap: 8px; margin: 0 0 12px; font-size: var(--text-sm); font-weight: var(--weight-bold); letter-spacing: var(--tracking-label); color: var(--c-muted); }
.kicker::before { content: ""; width: 18px; height: 2px; border-radius: var(--r-pill); background: var(--c-peach); flex-shrink: 0; }

.site-footer { margin-top: var(--section-gap); padding-top: 56px; padding-bottom: 96px; background: var(--c-panel); color: var(--c-text); border-top: var(--stroke) solid var(--c-lilac); }
.footer-grid { display: grid; grid-template-columns: 1.4fr 0.8fr 1.2fr 0.7fr; gap: 40px; }
.footer-brand p { max-width: 27em; margin: 18px 0 0; font-size: var(--text-label); color: var(--c-muted); }
.footer-title { margin: 0 0 16px; font-size: var(--text-label); font-weight: var(--weight-bold); }
.footer-links { list-style: none; padding: 0; margin: 0; }
.footer-links a { display: block; padding-top: 7px; padding-bottom: 7px; font-size: var(--text-label); color: var(--c-muted); overflow-wrap: anywhere; }
.footer-links a:hover { color: var(--c-signal); }
.footer-bottom { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 16px 28px; margin-top: 40px; padding-top: 24px; border-top: var(--stroke) solid var(--c-border); font-size: var(--text-sm); color: var(--c-muted); }
.footer-bottom p { margin: 0; }
.legal-links { display: flex; flex-wrap: wrap; gap: 20px; }
.legal-links a { color: var(--c-muted); }

.reveal { opacity: 1; transform: none; }
html.reveal-ready .reveal:not(.shown) { opacity: 0; transform: translateY(16px); }
.reveal { transition: opacity var(--duration-reveal) var(--ease), transform var(--duration-reveal) var(--ease); }

@media (max-width: 1180px) {
  .desktop-nav { display: none; }
  .header-tools { margin-left: auto; }
  .menu-toggle { display: inline-flex; }
  .brand { margin-right: 0; }
}
@media (min-width: 1181px) {
  .mobile-drawer, .nav-veil { display: none !important; }
}
@media (max-width: 900px) {
  .brand-sub { display: none; }
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 768px) {
  h1 { font-size: clamp(24px, 5vw, 30px); }
}
@media (max-width: 640px) {
  :root { --gutter: 20px; --drop: 18px; --card-pad: 22px; }
  .wrap, .header-wrap { padding-inline: var(--gutter); }
  .masthead-row { gap: 10px; }
  .brand { gap: 8px; font-size: var(--text-label); }
  .brand-mark { width: 30px; height: 30px; }
  .lang { margin-left: 0; min-height: 44px; padding-inline: 10px; }
  .lang-long { display: none; }
  .lang-short { display: inline; }
  .lang .globe { display: none; }
  .header-tools { gap: 6px; margin-left: auto; }
  .card-grid, .footer-grid { grid-template-columns: minmax(0, 1fr); }
  .footer-grid { gap: 28px; }
  .btn { min-height: 50px; font-size: var(--text-nav); padding-inline: 20px; }
  .tilt, [class*="--tilt"], .decor-tilt { transform: none !important; }
  pre { padding: 18px; }
  .site-footer { padding-bottom: 96px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
  html.reveal-ready .reveal:not(.shown) { opacity: 1; transform: none; }
}