:root {
  color-scheme: light;
  --bg: #ffffff;
  --bg-panel: #f7f7f7;
  --bg-panel-2: #efefef;
  --border: #e5e5e5;
  --line-grid: #ececec;
  --line-strong: #d4d4d4;
  --accent: #4a6b2c;
  --accent-dark: #2e4518;
  --accent-halo: rgba(74, 107, 44, .32);
  --sage: #c3ccb0;
  --stone: #d8cfbf;
  --board-sheen: rgba(255, 255, 255, .28);
  --text: #0d0d0d;
  --text-muted: #6b6b6b;
  --text-inverse: #ffffff;
  --ink-hover: #262626;
  --success: #2f8a4f;
  --warn: #b7791f;
  --error: #c2412d;
  --mask-ink: #000000;
  --clear: transparent;
  --veil: rgba(0, 0, 0, .2);
  --shadow-hair: 0 1px 2px rgba(0, 0, 0, .04);
  --shadow-float: 0 1px 2px rgba(0, 0, 0, .04), 0 12px 32px -16px rgba(0, 0, 0, .10), 0 40px 80px -40px rgba(0, 0, 0, .12);
  --shadow-mark: 0 1px 2px rgba(0, 0, 0, .05), 0 8px 20px -10px rgba(0, 0, 0, .16);
  --shadow-menu: 0 1px 2px rgba(0, 0, 0, .04), 0 18px 44px -18px rgba(0, 0, 0, .16);
  --font-display: "Inter", "Noto Sans SC", -apple-system, BlinkMacSystemFont, "PingFang SC", "PingFang TC", "Hiragino Sans", "Apple SD Gothic Neo", "Helvetica Neue", Arial, sans-serif;
  --font-body: "Inter", "Noto Sans SC", -apple-system, BlinkMacSystemFont, "PingFang SC", "PingFang TC", "Hiragino Sans", "Apple SD Gothic Neo", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --weight-normal: 400;
  --weight-medium: 500;
  --weight-strong: 600;
  --fs-xs: 12px;
  --fs-sm: 13px;
  --fs-label: 14px;
  --fs-ui: 15px;
  --fs-body: 16px;
  --fs-intro: 18px;
  --fs-h3: 22px;
  --fs-h2: clamp(26px, 3vw, 36px);
  --h1: clamp(34px, 3.4vw, 48px);
  --fs-rule: 22px;
  --fs-board: 220px;
  --fs-board-small: 72px;
  --track-tight: -.025em;
  --track-cjk: -.02em;
  --track-ui: -.01em;
  --r-pill: 999px;
  --r-circle: 50%;
  --r-box: 28px;
  --r-board: 24px;
  --r-menu: 20px;
  --r-item: 12px;
  --r-mark-sm: 7px;
  --r-mark: 12px;
  --r-shot: 10px;
  --r-tiny: 2px;
  --nav-h: 72px;
  --peek: 52px;
  --gutter: 32px;
  --reading-width: 1120px;
  --header-width: 1280px;
  --section-space: 160px;
  --duration: 220ms;
  --reveal-duration: 540ms;
  --ease: cubic-bezier(.2, .65, .3, 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(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: 1.65;
  -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(--clear); }
img, svg { max-width: 100%; }
img { height: auto; }
svg { vertical-align: middle; flex-shrink: 0; }
figure { margin: 0; }
button { color: var(--text); }
a:focus-visible, button:focus-visible, summary:focus-visible,
input:focus-visible, select:focus-visible, textarea:focus-visible,
[tabindex]:focus-visible {
  outline: 2px solid var(--text);
  outline-offset: 4px;
}
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: var(--weight-normal);
  letter-spacing: var(--track-cjk);
  line-height: 1.25;
  text-wrap: balance;
  overflow-wrap: break-word;
}
h1 { font-size: var(--h1); line-height: 1.14; }
h2 { font-size: var(--fs-h2); }
h3 { font-size: var(--fs-h3); }
p { margin-block: 0 1.25em; }
strong { font-weight: var(--weight-strong); }
code { font-family: var(--font-mono); overflow-wrap: anywhere; }
pre {
  max-width: 100%;
  min-width: 0;
  overflow-x: auto;
  padding: 24px;
  border: 1px solid var(--border);
  border-radius: var(--r-menu);
  background: var(--bg-panel);
  color: var(--text);
  font-family: var(--font-mono);
  font-size: var(--fs-label);
  line-height: 1.8;
  tab-size: 2;
}
pre code { overflow-wrap: normal; white-space: pre; }
ul, ol { padding-inline-start: 1.5em; }
.grid > *, .split > *, .footer-grid > *, .editorial-layout > * { min-width: 0; }
.wrap {
  width: 100%;
  max-width: calc(var(--reading-width) + var(--gutter) * 2);
  padding-inline: var(--gutter);
  margin-inline: auto;
}
.section { padding-top: var(--section-space); padding-bottom: 0; }
.section:last-child { padding-bottom: var(--section-space); }
.section-heading { max-width: 760px; margin-bottom: 48px; }
.section-heading h2 { margin-block: 0 18px; }
.section-heading p, .muted, .meta { color: var(--text-muted); }
.meta { font-size: var(--fs-sm); }
.keep { white-space: nowrap; }
h2 .keep { white-space: normal; }
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}
.skip-link {
  position: fixed;
  z-index: 100;
  left: var(--gutter);
  top: 8px;
  padding: 12px 20px;
  transform: translateY(-150%);
  border-radius: var(--r-pill);
  background: var(--text);
  color: var(--text-inverse);
}
.skip-link:focus { transform: translateY(0); }
.prose { min-width: 0; max-width: 780px; }
.prose h2 { margin-top: 2.7em; margin-bottom: .9em; }
.prose h3 { margin-top: 2em; }
.prose a:not(.btn):not(.app-store):not(.device-card) {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: .22em;
}
.prose li + li { margin-top: .6em; }
.prose > :first-child { margin-top: 0; }
.grid { display: grid; gap: 24px; }
.grid-two, .split { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 24px; }
.stack > * + * { margin-top: 24px; }
.panel, .card {
  padding: 32px;
  border: 1px solid var(--border);
  border-radius: var(--r-board);
  background: var(--bg);
  color: var(--text);
  box-shadow: var(--shadow-hair);
  min-width: 0;
}
.card h3, .panel h3 { margin-top: 0; }
.card > :last-child, .panel > :last-child { margin-bottom: 0; }
.card-link { display: block; }
.card-link:hover { border-color: var(--line-strong); }
.cta-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-top: 26px;
}
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  min-height: 48px;
  padding: 10px 24px;
  border: 1px solid var(--clear);
  border-radius: var(--r-pill);
  font-size: var(--fs-ui);
  font-weight: var(--weight-medium);
  line-height: 1.4;
  text-align: center;
  max-width: 100%;
}
.btn svg { width: 17px; height: 17px; }
.btn-solid {
  background: var(--text);
  color: var(--text-inverse);
}
.btn-solid:hover, .btn-solid.is-hover { background: var(--ink-hover); color: var(--text-inverse); }
.btn-line {
  background: var(--bg);
  color: var(--text);
  border-color: var(--border);
}
.btn-line:hover, .btn-line.is-hover { background: var(--bg-panel); color: var(--text); }
.btn:active { transform: translateY(1px); }
.btn:disabled, .btn[aria-disabled="true"] {
  background: var(--bg-panel-2);
  color: var(--text-muted);
  border-color: var(--border);
  cursor: not-allowed;
}
.btn.is-focus { outline: 2px solid var(--text); outline-offset: 4px; }
#site-header { position: relative; z-index: 50; }
.masthead {
  position: relative;
  z-index: 20;
  display: flex;
  align-items: center;
  gap: 0;
  width: 100%;
  max-width: min(100%, calc(var(--header-width) + var(--gutter) * 2));
  height: var(--nav-h);
  padding-inline: var(--gutter);
  margin-inline: auto;
  background: var(--bg);
  color: var(--text);
}
.brand { display: inline-flex; align-items: center; gap: 10px; flex-shrink: 0; }
.brand-mark { display: block; width: 28px; height: 28px; flex-shrink: 0; border-radius: var(--r-mark-sm); }
.brand-name {
  font-family: var(--font-display);
  font-size: var(--fs-ui);
  font-weight: var(--weight-medium);
  letter-spacing: var(--track-ui);
  white-space: nowrap;
}
.primary-nav { margin-left: 48px; min-width: 0; }
.primary-nav > ul {
  display: flex;
  align-items: center;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: 30px;
}
.nav-link {
  position: relative;
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  font-size: var(--fs-ui);
  color: var(--text);
  white-space: nowrap;
}
.nav-link:hover { color: var(--text-muted); }
.nav-link[aria-current="page"]::after,
.more.has-current > summary::after {
  content: "";
  position: absolute;
  inset-inline: 0;
  bottom: 4px;
  height: 2px;
  border-radius: var(--r-tiny);
  background: var(--accent);
}
.more { position: relative; }
.more > summary {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  min-height: 40px;
  font-size: var(--fs-ui);
  color: var(--text);
  cursor: pointer;
  list-style: none;
}
.more > summary::-webkit-details-marker { display: none; }
.more > summary svg { width: 12px; height: 12px; }
.more[open] > summary svg { transform: rotate(180deg); }
.more-panel, .language-panel {
  position: absolute;
  top: calc(100% + 12px);
  left: -18px;
  min-width: 248px;
  padding: 8px;
  margin: 0;
  list-style: none;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--r-menu);
  box-shadow: var(--shadow-menu);
  z-index: 25;
}
.more-panel a, .language-panel a {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 2px;
  min-height: 44px;
  width: 100%;
  padding: 10px 14px;
  border-radius: var(--r-item);
}
.more-panel a:hover, .language-panel a:hover { background: var(--bg-panel); color: var(--text); }
.more-title { font-size: var(--fs-label); }
.more-note { font-size: var(--fs-xs); color: var(--text-muted); }
.more-panel a[aria-current="page"] .more-title,
.language-panel a[aria-current="true"] { text-decoration: underline; text-underline-offset: 5px; }
.masthead-tools {
  display: flex;
  align-items: center;
  flex-shrink: 0;
  gap: 10px;
  margin-left: auto;
}
.language { position: relative; }
.lang {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 5px;
  min-height: 40px;
  padding: 0 16px;
  border: 0;
  border-radius: var(--r-pill);
  background: var(--bg-panel);
  color: var(--text);
  font-family: var(--font-body);
  font-size: var(--fs-label);
  white-space: nowrap;
}
.lang:hover { background: var(--bg-panel-2); color: var(--text); }
.lang-short { display: none; }
.language-panel { right: 0; left: auto; min-width: 180px; }
.nav-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 40px;
  padding: 8px 18px;
  border-radius: var(--r-pill);
  background: var(--text);
  color: var(--text-inverse);
  font-size: var(--fs-label);
  font-weight: var(--weight-medium);
  white-space: nowrap;
}
.nav-cta:hover { background: var(--ink-hover); color: var(--text-inverse); }
.nav-cta svg { width: 14px; height: 14px; }
.menu-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  min-height: 44px;
  padding: 10px;
  border: 1px solid var(--border);
  border-radius: var(--r-circle);
  background: var(--bg);
  color: var(--text);
}
.menu-toggle svg { width: 20px; height: 20px; }
.mobile-drawer {
  position: fixed;
  z-index: 24;
  top: var(--nav-h);
  inset-inline: 0;
  max-height: calc(100dvh - var(--nav-h));
  overflow-y: auto;
  overscroll-behavior: contain;
  padding: 16px var(--gutter) 32px;
  border-top: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
  box-shadow: var(--shadow-menu);
}
.mobile-drawer ul { padding: 0; margin: 0; list-style: none; }
.mobile-drawer a {
  display: flex;
  align-items: center;
  min-height: 48px;
  width: 100%;
  padding: 12px 8px;
  border-bottom: 1px solid var(--border);
}
.mobile-drawer a[aria-current] { text-decoration: underline; text-underline-offset: 5px; }
.drawer-caption { margin: 24px 8px 8px; color: var(--text-muted); font-size: var(--fs-sm); }
.menu-veil {
  position: fixed;
  z-index: 21;
  inset: var(--nav-h) 0 0;
  width: 100%;
  border: 0;
  padding: 0;
  background: var(--veil);
  color: var(--text);
}
.site-footer { margin-top: var(--section-space); border-top: 1px solid var(--border); }
.footer-inner {
  max-width: calc(var(--header-width) + var(--gutter) * 2);
  padding: 64px var(--gutter) 32px;
  margin-inline: auto;
}
.footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1.4fr; gap: 64px; }
.footer-brand p { max-width: 350px; margin-top: 20px; color: var(--text-muted); font-size: var(--fs-label); }
.footer-title { margin: 0 0 18px; font-size: var(--fs-label); font-weight: var(--weight-medium); }
.footer-links { padding: 0; margin: 0; list-style: none; }
.footer-links a { display: inline-block; padding-block: 5px; font-size: var(--fs-label); color: var(--text-muted); }
.footer-links a:hover { color: var(--text); text-decoration: underline; text-underline-offset: 4px; }
.footer-languages { display: flex; flex-wrap: wrap; gap: 8px 24px; margin-top: 48px; }
.footer-languages a { min-height: 44px; display: inline-flex; align-items: center; font-size: var(--fs-label); }
.footer-languages a[aria-current="true"] { text-decoration: underline; text-underline-offset: 5px; }
.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px 24px;
  margin-top: 24px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  font-size: var(--fs-xs);
  color: var(--text-muted);
}
.footer-bottom p { margin: 0; }
.reveal { opacity: 1; }
.reveal-ready .reveal:not(.shown) { opacity: 0; transform: translateY(16px); }
.reveal-ready .reveal {
  transition: opacity var(--reveal-duration) var(--ease), transform var(--reveal-duration) var(--ease);
}
.reveal.shown { opacity: 1; transform: none; }
.decorated { overflow-x: clip; position: relative; }
@media (max-width: 1280px) {
  .primary-nav { margin-left: 28px; }
  .primary-nav > ul { gap: 20px; }
  html:not([lang="zh-CN"]):not([lang="zh-TW"]) .primary-nav { display: none; }
  html:not([lang="zh-CN"]):not([lang="zh-TW"]) .menu-toggle { display: inline-flex; }
}
@media (max-width: 1100px) {
  .primary-nav { display: none; }
  .menu-toggle { display: inline-flex; }
  .masthead-tools { margin-left: auto; }
}
@media (max-width: 768px) {
  :root { --gutter: 20px; --h1: clamp(24px, 4.7vw, 30px); --section-space: 100px; }
  .grid-two, .split { grid-template-columns: minmax(0, 1fr); }
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 40px 24px; }
  .footer-brand { grid-column: 1 / -1; }
  .masthead-tools > .nav-cta { display: none; }
  .section-heading { margin-bottom: 32px; }
}
@media (max-width: 640px) {
  :root { --gutter: 16px; }
  .tilt, [data-tilt] { transform: none !important; }
  .panel, .card { padding: 24px; }
  .brand-name { font-size: var(--fs-label); }
  .lang-full { display: none; }
  .lang-short { display: inline; }
  .lang { padding-inline: 12px; min-height: 44px; }
  .masthead-tools { gap: 8px; margin-left: auto; }
  .footer-inner { padding-top: 48px; }
}
@media (max-width: 380px) {
  .masthead .brand-name { font-size: var(--fs-xs); }
  .masthead .brand { gap: 6px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal-ready .reveal:not(.shown), .reveal-ready .reveal { opacity: 1; transform: none; transition: none; }
}