:root {
  --bg: #ffffff;
  --panel: #f6f6f7;
  --panel2: #eeeef0;
  --border: #e4e4e7;
  --accent: #94408a;
  --accent-dark: #73306b;
  --text: #2f2e33;
  --muted: #77757d;
  --panel-ink: #6b6872;
  --success: #3e9a6a;
  --warn: #c98a1c;
  --error: #c8463d;
  --lichen: #9fd3cf;
  --on-accent: #ffffff;
  --sketch: #dad9de;
  --annot: #b4b2b9;
  --accent-mark: rgba(148, 64, 138, .15);
  --accent-ring: rgba(148, 64, 138, .35);
  --veil: rgba(47, 46, 51, .16);
  --clear: transparent;
  --shadow-float: 0 1px 2px rgba(47,46,51,.05), 0 14px 32px -10px rgba(47,46,51,.09), 0 56px 110px -30px rgba(47,46,51,.20);
  --shadow-back: 0 1px 2px rgba(47,46,51,.04), 0 24px 48px -24px rgba(47,46,51,.12);
  --shadow-btn: 0 1px 1px rgba(115,48,107,.18), 0 10px 22px -10px rgba(115,48,107,.55);
  --shadow-mark: 0 1px 2px rgba(47,46,51,.06), 0 6px 14px -8px rgba(47,46,51,.18);
  --shadow-fold: rgba(47,46,51,.14);
  --r-xl: 28px;
  --r-md: 14px;
  --r-sm: 8px;
  --r-icon: 9px;
  --r-shot: 10px;
  --r-pill: 999px;
  --r-round: 50%;
  --r-mark: 4px 10px 5px 9px;
  --font-display: "Inter","Noto Sans SC","PingFang SC","PingFang TC","Hiragino Sans","Apple SD Gothic Neo",system-ui,-apple-system,sans-serif;
  --font-body: "Inter","Noto Sans SC","PingFang SC","PingFang TC","Hiragino Sans","Hiragino Kaku Gothic ProN","Apple SD Gothic Neo",system-ui,-apple-system,sans-serif;
  --font-mono: "JetBrains Mono",ui-monospace,"SF Mono",Menlo,Consolas,monospace;
  --text-xs: 13px;
  --text-sm: 14px;
  --text-base: 16px;
  --text-lead: 20px;
  --weight-body: 400;
  --weight-medium: 500;
  --weight-semibold: 600;
  --weight-bold: 700;
  --tracking-title: -.02em;
  --leading-body: 1.6;
  --gutter: 32px;
  --content-width: 1120px;
  --reading-width: 800px;
  --header-width: 1280px;
  --header-height: 68px;
  --section-space: 168px;
  --panel-padding: 40px;
  --margin-w: 380px;
  --gutter-w: 64px;
  --motion-fast: .2s;
  --motion-reveal: .65s;
  --motion-ease: cubic-bezier(.2,.65,.3,1);
  --layer-header: 50;
  --layer-fab: 30;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 32px; }
html.nav-open { overflow: hidden; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
[hidden] { display: none !important; }
a { color: inherit; text-decoration: none; }
button, input, select, textarea { font: inherit; }
button { cursor: pointer; }
button, a { -webkit-tap-highlight-color: var(--accent-mark); }
button { color: var(--text); }
a:focus-visible, button:focus-visible, summary:focus-visible, [tabindex]:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 4px;
  border-radius: var(--r-sm);
}
img, svg { vertical-align: middle; max-width: 100%; }
img { height: auto; }
svg { flex-shrink: 0; }
figure { min-width: 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;
  background: var(--panel);
  color: var(--text);
  border-radius: var(--r-md);
  font-size: var(--text-sm);
  line-height: 1.85;
  tab-size: 2;
}
pre code { white-space: pre; overflow-wrap: normal; word-break: normal; }
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: var(--weight-bold);
  letter-spacing: var(--tracking-title);
  line-height: 1.22;
  text-wrap: balance;
}
h1 { font-size: clamp(34px, 2.2vw + 16px, 48px); line-height: 1.12; }
h2 { font-size: clamp(26px, 2.5vw, 36px); }
h3 { font-size: 23px; }
h4 { font-size: 18px; }
.nowrap, .kw { white-space: nowrap; }
.wrap {
  width: 100%;
  max-width: calc(var(--content-width) + var(--gutter) * 2);
  margin-inline: auto;
  padding-inline: var(--gutter);
  min-width: 0;
}
.reading { max-width: calc(var(--reading-width) + var(--gutter) * 2); }
.section { padding-top: var(--section-space); padding-bottom: 0; }
.section:last-child { padding-bottom: var(--section-space); }
.section-heading { max-width: 740px; margin: 0 auto 48px; text-align: center; }
.section-heading p { margin-top: 18px; color: var(--muted); }
.stack > * + * { margin-top: 24px; }
.grid-two { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 28px; }
.grid-two > *, .prose *, .panel > *, .card > * { min-width: 0; }
.prose { min-width: 0; line-height: 1.9; }
.prose > * + *, .prose section > * + * { margin-top: 20px; }
.prose h2 { margin-top: 72px; }
.prose h3 { margin-top: 36px; }
.prose ul, .prose ol { padding-left: 1.5em; }
.prose li + li { margin-top: 8px; }
.prose a, .text-link { color: var(--accent); text-decoration: underline; text-underline-offset: .22em; }
.prose :not(pre) > code { background: var(--panel); color: var(--text); border-radius: var(--r-sm); padding: .1em .3em; }
.prose section, [id] { scroll-margin-top: 32px; }
.muted { color: var(--muted); }
.lead { font-size: var(--text-lead); line-height: 1.75; }
.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;
  top: 8px;
  left: var(--gutter);
  z-index: 100;
  padding: 12px 18px;
  transform: translateY(-160%);
  background: var(--accent);
  color: var(--on-accent);
  border-radius: var(--r-sm);
}
.skip-link:focus { transform: none; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 50px;
  max-width: 100%;
  padding: 11px 24px;
  border: 0;
  border-radius: var(--r-md);
  font-size: var(--text-base);
  font-weight: var(--weight-semibold);
  letter-spacing: -.005em;
  line-height: 1.5;
  text-align: center;
  transition: background-color var(--motion-fast), box-shadow var(--motion-fast), color var(--motion-fast);
}
.btn-primary { background: var(--accent); color: var(--on-accent); box-shadow: var(--shadow-btn); }
.btn-primary:hover, .btn-primary.is-hover { background: var(--accent-dark); color: var(--on-accent); }
.btn-ghost { background: var(--bg); color: var(--text); box-shadow: inset 0 0 0 1px var(--border); }
.btn-ghost:hover, .btn-ghost.is-hover { background: var(--panel); color: var(--text); }
.btn:active { box-shadow: inset 0 0 0 2px var(--accent-ring); }
.btn:disabled, .btn[aria-disabled="true"] { background: var(--panel2); color: var(--panel-ink); box-shadow: none; cursor: not-allowed; }
.btn.is-focus { outline: 2px solid var(--accent); outline-offset: 4px; }
.btn-apple { width: 18px; height: 18px; margin-top: -2px; flex: none; }
.btn-chev { width: 14px; height: 14px; color: var(--muted); flex: none; }
.cta { display: flex; justify-content: center; flex-wrap: wrap; gap: 12px; margin-bottom: 18px; }

#site-header { position: relative; z-index: var(--layer-header); background: var(--bg); color: var(--text); }
.masthead {
  position: relative;
  width: 100%;
  max-width: min(100%, calc(var(--header-width) + var(--gutter) * 2));
  min-height: var(--header-height);
  margin: 0 auto;
  padding-inline: var(--gutter);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 26px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: var(--weight-bold);
  letter-spacing: -.01em;
  color: var(--text);
}
.brand-mark {
  display: block;
  width: 32px;
  height: 32px;
  flex: none;
  border-radius: var(--r-icon);
}
.brand-placeholder {
  background: linear-gradient(180deg, var(--bg), var(--panel));
  color: var(--text);
  box-shadow: inset 0 0 0 1px var(--border), var(--shadow-mark);
}
.nav { display: flex; align-items: center; min-width: 0; margin-left: auto; }
.nav-list {
  display: flex;
  align-items: center;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: 34px;
}
.nav-list a {
  display: block;
  padding-block: 12px;
  white-space: nowrap;
  font-size: 15px;
  font-weight: 450;
  color: var(--text);
  transition: color var(--motion-fast);
}
.nav-list a:hover { color: var(--accent); }
.nav-list a[aria-current="page"] { font-weight: 680; }
.header-tools { display: flex; align-items: center; gap: 12px; flex-shrink: 0; margin-left: 18px; }
.language-picker { position: relative; }
.lang {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  min-height: 44px;
  border: 0;
  background: var(--bg);
  color: var(--muted);
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  white-space: nowrap;
}
.lang:hover { color: var(--text); }
.lang-caret { font-size: 11px; }
.lang-short { display: none; }
.language-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  width: 192px;
  padding: 8px;
  list-style: none;
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  background: var(--bg);
  color: var(--text);
  box-shadow: var(--shadow-back);
}
.language-menu a { display: flex; align-items: center; min-height: 44px; padding: 10px 14px; border-radius: var(--r-sm); }
.language-menu a:hover { background: var(--panel); color: var(--text); }
.language-menu [aria-current="true"] { font-weight: var(--weight-bold); color: var(--accent); }
.menu-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  min-height: 44px;
  border: 0;
  border-radius: var(--r-sm);
  background: var(--bg);
  color: var(--text);
}
.menu-toggle svg { width: 22px; height: 22px; }
.mobile-drawer {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  z-index: 2;
  max-height: calc(100dvh - var(--header-height));
  padding: 16px var(--gutter) 24px;
  overflow-y: auto;
  overscroll-behavior: contain;
  background: var(--bg);
  color: var(--text);
  border-top: 1px solid var(--border);
  box-shadow: var(--shadow-back);
}
.mobile-drawer ul { list-style: none; }
.mobile-drawer a { display: flex; align-items: center; width: 100%; min-height: 48px; padding: 12px 8px; }
.mobile-drawer a[aria-current] { color: var(--accent); font-weight: var(--weight-semibold); }
.drawer-languages { margin-top: 16px; padding-top: 16px; border-top: 1px solid var(--border); }
.nav-veil { position: fixed; inset: var(--header-height) 0 0; z-index: 0; border: 0; background: var(--veil); color: var(--text); }

.hero { position: relative; padding: 44px 24px 168px; text-align: center; overflow-x: clip; }
.hero-inner { position: relative; max-width: 1200px; margin: 0 auto; min-width: 0; }
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  min-height: 30px;
  padding: 4px 14px 4px 12px;
  margin-bottom: 22px;
  border-radius: var(--r-pill);
  background: var(--panel);
  color: var(--panel-ink);
  font-size: var(--text-xs);
  font-weight: var(--weight-medium);
}
.eyebrow-dot { width: 7px; height: 7px; flex-shrink: 0; border-radius: var(--r-round); background: var(--accent); color: var(--on-accent); }
.hero-title { font-size: clamp(30px, 2.2vw + 16px, 48px); margin-bottom: 28px; }
.kw { position: relative; display: inline-block; isolation: isolate; }
.kw-stroke { position: absolute; left: -5%; width: 110%; bottom: -.24em; height: .36em; color: var(--lichen); z-index: -1; overflow: visible; }
.facts { font-size: 15px; color: var(--muted); margin-bottom: 22px; }
.facts strong { color: var(--text); font-weight: var(--weight-semibold); }
.facts-sep { margin: 0 10px; color: var(--annot); }
.devices { display: inline-flex; align-items: center; gap: 26px; list-style: none; margin-bottom: 42px; }
.device { display: inline-flex; align-items: center; gap: 8px; font-size: 14.5px; font-weight: var(--weight-medium); color: var(--text); }
.device svg { width: 20px; height: 20px; color: var(--muted); flex: none; }
.device:hover, .device:hover svg { color: var(--accent); }
.devices-rule { width: 1px; height: 18px; background: var(--border); color: var(--text); }
.chip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  min-height: 30px;
  max-width: 100%;
  padding: 4px 13px;
  border-radius: var(--r-pill);
  background: var(--panel);
  color: var(--text);
  font-size: var(--text-xs);
  font-weight: var(--weight-medium);
  overflow-wrap: anywhere;
}
.chip svg { width: 13px; height: 13px; margin-top: -1px; flex-shrink: 0; }
.chips { display: inline-flex; flex-wrap: wrap; gap: 8px; }
.doodle { position: absolute; color: var(--sketch); pointer-events: none; overflow: visible; }
.doodle-brace { left: 34px; top: 92px; width: 44px; height: 128px; }
.doodle-check { right: 40px; top: 146px; width: 96px; height: 78px; }
.stage { position: relative; max-width: 1120px; margin: 0 auto; text-align: left; }
.sheet-back { position: absolute; inset: 0; border-radius: var(--r-xl); background: var(--panel2); color: var(--text); transform: translate(-14px,16px) rotate(-1.5deg); box-shadow: var(--shadow-back); }
.sheet { position: relative; background: var(--bg); color: var(--text); border-radius: var(--r-xl); box-shadow: var(--shadow-float); overflow: hidden; }
.sheet-head { position: relative; display: flex; align-items: center; gap: 18px; height: 52px; padding-inline: 28px; border-bottom: 1px solid var(--border); }
.dots { display: flex; gap: 7px; flex-shrink: 0; }
.dots i { width: 10px; height: 10px; flex-shrink: 0; border-radius: var(--r-round); opacity: .5; }
.dots .d1 { background: var(--error); color: var(--text); }
.dots .d2 { background: var(--warn); color: var(--text); }
.dots .d3 { background: var(--success); color: var(--text); }
.fname { font-family: var(--font-mono); font-size: 13.5px; font-weight: var(--weight-medium); }
.fmeta { margin-left: auto; margin-right: 60px; font-family: var(--font-mono); font-size: 12.5px; color: var(--muted); }
.fold { position: absolute; top: 0; right: 0; width: 52px; height: 52px; }
.fold-cut { fill: var(--bg); }
.fold-flap { fill: var(--panel2); stroke: var(--border); stroke-width: 1; filter: drop-shadow(-2px 4px 4px var(--shadow-fold)); }
.sheet-body { position: relative; padding-top: 16px; padding-bottom: 48px; font-family: var(--font-mono); font-size: 15px; line-height: 30px; background: linear-gradient(to right,var(--panel) 0,var(--panel) var(--gutter-w),var(--clear) var(--gutter-w)); color: var(--text); }
.sheet-body::after { content: ""; position: absolute; top: 0; bottom: 0; right: var(--margin-w); width: 1px; background: var(--panel2); }
.row { display: grid; grid-template-columns: var(--gutter-w) minmax(0,1fr) var(--margin-w); align-items: center; min-height: 30px; }
.row > * { min-width: 0; }
.ln { text-align: right; padding-right: 18px; font-size: 12.5px; color: var(--annot); user-select: none; }
.code { display: block; padding-left: 28px; padding-right: 8px; white-space: pre; overflow-x: auto; overflow-wrap: normal; color: var(--text); scrollbar-width: thin; }
.sec { font-weight: var(--weight-bold); }
.kwd { font-weight: var(--weight-semibold); }
.op { color: var(--muted); }
.pol { font-weight: var(--weight-medium); }
.mark { position: relative; z-index: 0; }
.mark::before { content: ""; position: absolute; top: 1px; bottom: 1px; left: -8px; right: -12px; border-radius: var(--r-mark); background: var(--accent-mark); transform: rotate(-.8deg); z-index: -1; }
.note { position: relative; z-index: 1; display: flex; align-items: center; gap: 8px; margin-left: -46px; font-family: var(--font-body); font-size: 14.5px; line-height: 1.3; color: var(--muted); }
.note svg { width: 66px; height: 30px; flex: none; color: var(--annot); overflow: visible; }
.note-text { display: inline-block; transform: rotate(-1.6deg); }
.note-b .note-text { transform: rotate(1.2deg); }
.note-c .note-text { transform: rotate(-.8deg); }

.panel, .card { min-width: 0; padding: var(--panel-padding); border-radius: var(--r-xl); background: var(--bg); color: var(--text); box-shadow: var(--shadow-back); }
.panel-float { box-shadow: var(--shadow-float); }
.inset { min-width: 0; padding: 28px; border-radius: var(--r-md); background: var(--panel); color: var(--text); }
.card h3 + p { margin-top: 16px; }
.card p { color: var(--muted); }
.card .text-link { display: inline-block; margin-top: 24px; }
.reveal { opacity: 1; transform: none; }
.reveal-ready .reveal:not(.shown) { opacity: 0; transform: translateY(18px); }
.reveal-ready .reveal { transition: opacity var(--motion-reveal) var(--motion-ease), transform var(--motion-reveal) var(--motion-ease); }

.site-footer { margin-top: var(--section-space); padding-top: 64px; padding-bottom: 32px; background: var(--bg); color: var(--text); border-top: 1px solid var(--border); }
.footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1.4fr; gap: 56px; }
.footer-grid > * { min-width: 0; }
.footer-intro p { max-width: 350px; margin-top: 20px; color: var(--muted); font-size: var(--text-sm); }
.footer-title { font-size: var(--text-sm); margin-bottom: 16px; }
.footer-links { list-style: none; display: flex; flex-wrap: wrap; gap: 10px 20px; }
.footer-links a { display: inline-block; padding-block: 5px; font-size: var(--text-sm); color: var(--muted); }
.footer-links a:hover { color: var(--accent); }
.footer-languages { display: flex; flex-wrap: wrap; gap: 8px 24px; margin-top: 40px; }
.footer-languages a { min-height: 44px; display: inline-flex; align-items: center; font-size: var(--text-sm); }
.footer-languages [aria-current="true"] { color: var(--accent); font-weight: var(--weight-semibold); }
.footer-bottom { display: flex; align-items: baseline; justify-content: space-between; gap: 16px; flex-wrap: wrap; margin-top: 24px; padding-top: 24px; border-top: 1px solid var(--border); color: var(--muted); font-size: var(--text-xs); }
.footer-legal { display: flex; flex-wrap: wrap; gap: 20px; }

@media (max-width: 1280px) {
  .masthead { gap: 18px; }
  .nav-list { gap: 22px; }
  .header-tools { margin-left: 0; }
  html:not([lang="zh-CN"]):not([lang="zh-TW"]) .masthead > .nav { display: none; }
  html:not([lang="zh-CN"]):not([lang="zh-TW"]) .menu-toggle { display: inline-flex; }
  html:not([lang="zh-CN"]):not([lang="zh-TW"]) .header-tools { margin-left: auto; }
}
@media (min-width: 1281px) {
  .mobile-drawer, .nav-veil { display: none !important; }
}
@media (max-width: 1180px) {
  .doodle { display: none; }
  .sheet-body { --margin-w: 300px; }
}
@media (max-width: 1080px) {
  .masthead > .nav { display: none; }
  .menu-toggle { display: inline-flex; }
  .header-tools { margin-left: auto; }
}
@media (max-width: 860px) {
  :root { --gutter: 20px; --section-space: 112px; --panel-padding: 28px; }
  .hero { padding: 32px 16px 96px; }
  .facts-sep { margin-inline: 6px; }
  .devices { flex-wrap: wrap; justify-content: center; gap: 14px 20px; }
  .devices-rule { display: none; }
  .sheet-head { padding-inline: 20px; }
  .fmeta { display: none; }
  .sheet-body { --gutter-w: 40px; font-size: var(--text-xs); line-height: 26px; }
  .sheet-body::after { display: none; }
  .row { grid-template-columns: var(--gutter-w) minmax(0,1fr); min-height: 26px; }
  .ln { padding-right: 10px; font-size: 11px; }
  .code { padding-left: 14px; }
  .note { grid-column: 2; margin-left: 0; padding: 0 14px 6px; font-size: var(--text-xs); }
  .note svg { display: none; }
  .sheet-back { transform: translate(-8px,10px) rotate(-1.5deg); }
  .footer-grid { grid-template-columns: minmax(0,1fr) minmax(0,1fr); gap: 32px; }
  .footer-intro { grid-column: 1 / -1; }
}
@media (max-width: 768px) {
  h1, .hero-title { font-size: clamp(24px, 4vw, 30px); }
  .grid-two { grid-template-columns: minmax(0,1fr); }
}
@media (max-width: 640px) {
  :root { --gutter: 16px; --panel-padding: 24px; }
  .tilt, .sheet-back, .note-text, .note-b .note-text, .note-c .note-text, .mark::before { transform: none; }
  .sheet-back { inset: 8px 4px -8px; }
  .section-heading { margin-bottom: 32px; }
  .brand { gap: 8px; font-size: 15px; }
  .masthead { gap: 8px; }
  .header-tools { gap: 4px; margin-left: auto; }
  .lang-full { display: none; }
  .lang-short { display: inline; }
  .lang { padding-inline: 6px; }
  .footer-grid { grid-template-columns: minmax(0,1fr); }
  .footer-intro { grid-column: auto; }
  .inset { padding: 20px; }
}
@media (max-width: 480px) {
  .btn { min-height: 46px; padding: 10px 18px; font-size: 15px; }
  .hero-title { font-size: 30px; }
  .brand-name { font-size: 15px; }
}
@media (max-width: 359px) {
  .brand-name { font-size: 13px; }
  .brand-mark { width: 28px; height: 28px; }
  .hero-title { font-size: 26px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
  .reveal-ready .reveal:not(.shown) { opacity: 1; transform: none; }
}