:root {
  color-scheme: light;
  --bg: #F8F9F8;
  --bg-panel: #FFFFFF;
  --bg-panel-2: #EEF2EF;
  --border: #DCE3DE;
  --accent: #17B47F;
  --accent-dark: #0B7A53;
  --mint-soft: #7FE3B8;
  --mint-pale: #CFF3E1;
  --pine: #0F2A1F;
  --text: #121814;
  --text-muted: #5A655E;
  --ink-soft: #2E3B33;
  --success: #1E9E5A;
  --warn: #C98A0B;
  --error: #D2413F;
  --on-dark: #FFFFFF;
  --on-dark-muted: #A9CBBB;
  --flag-red: #D52B3A;
  --flag-sun: #C4122F;
  --flag-white: #FFFFFF;
  --flag-blue: #1F3A80;
  --flag-green: #16884A;
  --transparent: transparent;
  --font-display: "Inter", "Noto Sans SC", "PingFang SC", "Hiragino Sans", "Apple SD Gothic Neo", "Microsoft YaHei", "Malgun Gothic", system-ui, sans-serif;
  --font-body: "Inter", "Noto Sans SC", "PingFang SC", "Hiragino Sans", "Yu Gothic", "Apple SD Gothic Neo", "Microsoft YaHei", "Malgun Gothic", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  --weight-body: 400;
  --weight-medium: 500;
  --weight-semibold: 600;
  --weight-bold: 700;
  --weight-heavy: 800;
  --weight-display: 900;
  --r-xs: 4px;
  --r-sm: 6px;
  --r-md: 8px;
  --r-lg: 12px;
  --r-flag: 3px;
  --r-pill: 999px;
  --r-round: 50%;
  --container: 1240px;
  --gutter: 32px;
  --header-height: 72px;
  --anchor-offset: 88px;
  --toc-offset: 88px;
  --section-space: 80px;
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 32px;
  --space-7: 48px;
  --space-8: 64px;
  --text-xs: 12px;
  --text-sm: 14px;
  --text-base: 16px;
  --text-lg: 18px;
  --leading-body: 1.6;
  --leading-reading: 1.85;
  --leading-title: 1.14;
  --tracking-title: -0.02em;
  --shadow-panel: 0 0 0 1px color-mix(in srgb, var(--border) 70%, transparent), 0 2px 6px color-mix(in srgb, var(--pine) 6%, transparent), 0 32px 48px -10px color-mix(in srgb, var(--accent) 12%, transparent);
  --shadow-float: 0 1px 2px color-mix(in srgb, var(--pine) 8%, transparent), 0 22px 48px -12px color-mix(in srgb, var(--accent) 12%, transparent), 0 14px 28px -16px color-mix(in srgb, var(--pine) 22%, transparent);
  --shadow-button: inset 0 1px 0 color-mix(in srgb, var(--on-dark) 30%, transparent), 0 12px 26px -10px color-mix(in srgb, var(--accent) 60%, transparent);
  --hl-inner: inset 0 1px 0 var(--bg-panel);
  --focus-ring: 2px solid var(--accent-dark);
  --ease-out: cubic-bezier(.2, .7, .2, 1);
  --duration-ui: 180ms;
  --duration-reveal: 480ms;
}

*, *::before, *::after { box-sizing: border-box; }
html {
  -webkit-text-size-adjust: 100%;
  scroll-padding-top: var(--anchor-offset);
  scroll-behavior: smooth;
}
html.nav-open { overflow: hidden; }
body {
  margin: 0;
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  color: var(--text);
  background:
    radial-gradient(ellipse 46% 38% at 80% 16%, color-mix(in srgb, var(--accent) 7%, transparent), transparent 70%),
    linear-gradient(180deg, color-mix(in srgb, var(--accent) 5%, var(--bg)) 0, var(--bg) 640px) no-repeat,
    var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
a { color: inherit; text-underline-offset: .2em; }
button, input, select, textarea { font: inherit; color: inherit; }
button, summary { cursor: pointer; }
button { border: 0; }
button, input, select, textarea { max-width: 100%; }
img { display: block; max-width: 100%; height: auto; }
svg { flex-shrink: 0; vertical-align: middle; }
[hidden] { display: none !important; }
:where(a, button, input, select, textarea, summary, [tabindex]):focus-visible {
  outline: var(--focus-ring);
  outline-offset: 3px;
  border-radius: var(--r-xs);
}
::selection { color: var(--pine); background: var(--mint-pale); }
h1, h2, h3, h4 {
  font-family: var(--font-display);
  color: var(--text);
  line-height: 1.25;
  font-weight: var(--weight-heavy);
  text-wrap: balance;
  overflow-wrap: break-word;
}
h1 {
  margin: 0 0 var(--space-5);
  font-size: clamp(52px, 4.1vw, 58px);
  font-weight: var(--weight-display);
  line-height: var(--leading-title);
  letter-spacing: var(--tracking-title);
}
h2 { margin: 0 0 var(--space-5); font-size: clamp(28px, 3vw, 40px); letter-spacing: var(--tracking-title); }
h3 { margin: 0 0 var(--space-3); font-size: 22px; }
h4 { margin: 0 0 var(--space-2); font-size: var(--text-lg); }
p { margin: 0 0 var(--space-4); }
ul, ol { padding-left: 1.5em; }
code {
  font-family: var(--font-mono);
  font-size: .88em;
  overflow-wrap: anywhere;
  background: var(--bg-panel-2);
  border-radius: var(--r-xs);
  padding: .15em .3em;
}
pre {
  max-width: 100%;
  overflow-x: auto;
  padding: var(--space-5);
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  background: var(--bg-panel-2);
  -webkit-overflow-scrolling: touch;
}
pre code { padding: 0; white-space: pre; overflow-wrap: normal; }
hr { border: 0; border-top: 1px solid var(--border); margin: var(--space-6) 0; }
.no-break { white-space: nowrap; }
.wrap {
  width: min(calc(var(--container) + var(--gutter) * 2), 100%);
  padding-inline: var(--gutter);
  margin-inline: auto;
  position: relative;
}
.section { padding-top: var(--section-space); padding-bottom: var(--section-space); }
.section-heading { max-width: 760px; margin-bottom: var(--space-7); }
.section-heading p { color: var(--text-muted); font-size: var(--text-lg); }
.reading-wrap { max-width: 880px; margin-inline: auto; }
.prose { line-height: var(--leading-reading); overflow-wrap: break-word; min-width: 0; }
.prose h2 { margin-top: var(--space-8); }
.prose h3 { margin-top: var(--space-6); }
.prose li + li { margin-top: var(--space-2); }
.prose a { color: var(--accent-dark); }
.prose > :first-child { margin-top: 0; }
.muted { color: var(--text-muted); }
.mono { font-family: var(--font-mono); font-variant-numeric: tabular-nums; }
.grid-2, .grid-3, .grid-5 { display: grid; gap: var(--space-5); }
.grid-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid-5 { grid-template-columns: repeat(5, minmax(0, 1fr)); }
:where(.grid-2, .grid-3, .grid-5) > * { min-width: 0; }
.panel {
  padding: var(--space-6);
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  box-shadow: var(--hl-inner), var(--shadow-float);
  min-width: 0;
}
.panel-soft { background: var(--bg-panel-2); box-shadow: var(--hl-inner); }
.decor-section { position: relative; overflow-x: clip; }
.sprite { position: absolute; width: 0; height: 0; overflow: hidden; }
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}
.skip-link {
  position: absolute;
  z-index: 100;
  inset-inline-start: var(--gutter);
  top: 0;
  padding: var(--space-3) var(--space-4);
  background: var(--bg-panel);
  color: var(--accent-dark);
  transform: translateY(-120%);
}
.skip-link:focus { transform: translateY(0); }
.cta-row { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 26px; }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  gap: 8px;
  min-height: 50px;
  padding: 10px 26px;
  border-radius: var(--r-pill);
  font-size: var(--text-base);
  font-weight: var(--weight-bold);
  text-decoration: none;
  letter-spacing: .01em;
  white-space: nowrap;
  border: 0;
  cursor: pointer;
}
.btn svg { display: block; }
.btn-primary {
  color: var(--on-dark);
  background: linear-gradient(135deg, var(--accent), var(--accent-dark));
  box-shadow: var(--shadow-button);
}
.btn-primary:hover, .btn-primary.is-hover {
  background: linear-gradient(135deg, var(--accent-dark), var(--accent-dark));
}
.btn-ghost, .btn-secondary {
  color: var(--text);
  background: var(--bg-panel);
  box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--text) 22%, transparent);
}
.btn-ghost:hover, .btn-secondary:hover { box-shadow: inset 0 0 0 1px var(--text); }
.btn:active { transform: translateY(1px); }
.btn:disabled, .btn[aria-disabled="true"] {
  color: var(--text-muted);
  background: var(--bg-panel-2);
  box-shadow: inset 0 0 0 1px var(--border);
  cursor: not-allowed;
}
.btn-small { min-height: 40px; padding: 8px 18px; font-size: var(--text-sm); }
.arrow-title {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  font-weight: var(--weight-heavy);
  color: var(--text);
  text-decoration: none;
  letter-spacing: -.01em;
}
.arrow-title .arr { font-weight: var(--weight-semibold); }
.arrow-title:hover .arr { color: var(--accent-dark); }
.badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 28px;
  padding: 3px 13px 3px 11px;
  border-radius: var(--r-pill);
  background: var(--bg-panel);
  border: 1px solid var(--border);
  font-size: 13px;
  font-weight: var(--weight-medium);
  color: var(--ink-soft);
  max-width: 100%;
  overflow-wrap: anywhere;
  box-shadow: 0 6px 16px -10px color-mix(in srgb, var(--accent) 40%, transparent);
}
.badge-dot { flex: none; width: 8px; height: 8px; border-radius: var(--r-round); background: var(--accent); box-shadow: 0 0 0 3px var(--mint-pale); }
.badge-sep { color: var(--text-muted); }
.tag {
  display: inline-block;
  font-size: 11px;
  font-weight: var(--weight-bold);
  color: var(--accent-dark);
  background: var(--mint-pale);
  padding: 2px 8px;
  border-radius: var(--r-pill);
  max-width: 100%;
  overflow-wrap: anywhere;
}
.topbar { position: relative; z-index: 40; }
.topbar-in { display: flex; align-items: center; min-height: var(--header-height); gap: 32px; }
.brand { display: inline-flex; align-items: center; gap: 8px; text-decoration: none; color: var(--text); flex: none; min-height: 40px; }
.brand img { width: 28px; height: 28px; flex-shrink: 0; }
.brand-en { font-family: var(--font-display); font-weight: var(--weight-display); font-size: 20px; letter-spacing: -.03em; line-height: 1; }
.brand-zh { font-size: var(--text-sm); font-weight: var(--weight-medium); color: var(--text-muted); line-height: 1; padding-left: 10px; margin-left: 2px; border-left: 1px solid var(--border); }
.mainnav { margin: 0 auto; }
.mainnav ul { display: flex; align-items: center; list-style: none; margin: 0; padding: 0; }
.mainnav li { display: flex; align-items: center; }
.mainnav li + li::before { content: "·"; margin: 0 13px; color: color-mix(in srgb, var(--text-muted) 55%, transparent); font-weight: var(--weight-bold); }
.mainnav a { font-size: 15px; font-weight: var(--weight-medium); color: var(--ink-soft); text-decoration: none; padding: 6px 1px; white-space: nowrap; }
.mainnav a:hover { color: var(--accent-dark); }
.mainnav a[aria-current="page"] { color: var(--text); font-weight: var(--weight-bold); box-shadow: inset 0 -2px 0 var(--mint-soft); }
.topbar-end { display: flex; align-items: center; gap: 18px; flex: none; }
.language-box { position: relative; }
.lang {
  appearance: none;
  background: none;
  border: 0;
  font: inherit;
  font-size: var(--text-sm);
  color: var(--ink-soft);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  min-width: 44px;
  min-height: 44px;
  width: auto;
  padding: 6px 4px;
  cursor: pointer;
}
.lang span { white-space: nowrap; }
.lang-caret { font-size: 11px; color: var(--text-muted); }
.language-menu {
  position: absolute;
  top: 100%;
  right: 0;
  min-width: 180px;
  padding: 8px;
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  box-shadow: var(--shadow-float);
  z-index: 60;
}
.language-menu a { display: flex; align-items: center; min-height: 44px; padding: 8px 12px; text-decoration: none; border-radius: var(--r-sm); }
.language-menu a:hover, .language-menu a[aria-current="true"] { background: var(--mint-pale); color: var(--accent-dark); }
.login {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 40px;
  padding: 0 22px;
  border-radius: var(--r-pill);
  background: var(--mint-pale);
  color: var(--accent-dark);
  font-weight: var(--weight-heavy);
  font-size: 15px;
  text-decoration: none;
  white-space: nowrap;
  box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--accent) 30%, transparent), 0 8px 18px -12px color-mix(in srgb, var(--accent) 70%, transparent);
}
.login:hover { background: color-mix(in srgb, var(--mint-pale) 80%, var(--mint-soft)); }
.menu-toggle { display: none; min-width: 44px; min-height: 44px; border-radius: var(--r-md); background: var(--bg-panel); color: var(--text); align-items: center; justify-content: center; }
.mobile-nav { display: none; }
.nav-veil { position: fixed; inset: var(--header-height) 0 0; z-index: 41; background: color-mix(in srgb, var(--pine) 28%, transparent); }
.site-footer { padding-top: 64px; padding-bottom: 24px; border-top: 1px solid var(--border); background: var(--bg-panel-2); }
.footer-grid { display: grid; grid-template-columns: 1.25fr 1fr 1.2fr .8fr; gap: 40px; }
.footer-grid > * { min-width: 0; }
.footer-brand p { margin: 16px 0 0; color: var(--text-muted); max-width: 300px; font-size: var(--text-sm); }
.footer-heading { font-size: var(--text-sm); margin: 0 0 12px; font-weight: var(--weight-heavy); color: var(--text); }
.footer-links { display: grid; gap: 4px; list-style: none; margin: 0; padding: 0; }
.footer-links a { display: inline-flex; align-items: center; min-height: 28px; font-size: var(--text-sm); text-decoration: none; color: var(--ink-soft); overflow-wrap: anywhere; }
.footer-links a:hover { color: var(--accent-dark); text-decoration: underline; }
.footer-bottom { border-top: 1px solid var(--border); margin-top: 40px; padding-top: 20px; display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 12px 24px; font-size: var(--text-xs); color: var(--text-muted); }
.footer-legal { display: flex; flex-wrap: wrap; gap: 16px; }
.footer-legal a { display: inline-flex; align-items: center; min-height: 28px; }
.reveal { transition: opacity var(--duration-reveal) var(--ease-out), transform var(--duration-reveal) var(--ease-out); }
.reveal.pending { opacity: 0; transform: translateY(16px); }
.reveal.shown { opacity: 1; transform: none; }
#server-status { display: block; position: static; min-width: 0; max-width: 100%; min-height: 160px; overflow: hidden; margin: 24px 0; }
#server-status + * { margin-top: 32px; }
#server-status > * { min-width: 0; max-width: 100%; }
[data-count] { display: inline-block; min-width: 3ch; font-family: var(--font-mono); font-variant-numeric: tabular-nums; text-align: right; }
@media (max-width: 1100px) {
  .topbar-in { gap: 18px; }
  .mainnav li + li::before { margin: 0 8px; }
  .topbar-end { gap: 12px; }
}
@media (max-width: 960px) {
  .mainnav { display: none; }
  .topbar-end { margin-left: auto; gap: 10px; position: relative; z-index: 44; }
  .brand { position: relative; z-index: 44; }
  .menu-toggle { display: inline-flex; }
  .topbar-in { position: relative; background: var(--bg); }
  .mobile-nav:not([hidden]) {
    display: block;
    position: absolute;
    top: 100%;
    left: var(--gutter);
    right: var(--gutter);
    z-index: 43;
    max-height: calc(100dvh - var(--header-height) - 16px);
    overflow-y: auto;
    overscroll-behavior: contain;
    background: var(--bg-panel);
    border: 1px solid var(--border);
    border-radius: var(--r-lg);
    padding: 12px;
    box-shadow: var(--shadow-float);
  }
  .mobile-nav ul { list-style: none; padding: 0; margin: 0; }
  .mobile-nav a { display: flex; align-items: center; width: 100%; min-height: 44px; padding: 10px 14px; text-decoration: none; border-radius: var(--r-sm); }
  .mobile-nav a:hover, .mobile-nav a[aria-current] { background: var(--mint-pale); color: var(--accent-dark); }
  .mobile-languages { margin-top: 12px; padding-top: 12px; border-top: 1px solid var(--border); }
  .mobile-caption { padding: 8px 14px; color: var(--text-muted); font-size: var(--text-xs); }
  .grid-5 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 32px; }
}
@media (max-width: 768px) {
  :root { --gutter: 24px; --section-space: 56px; }
  h1 { font-size: clamp(28px, 5.2vw, 40px); }
  h2 { font-size: clamp(26px, 4.8vw, 32px); }
  .grid-3 { grid-template-columns: 1fr; }
  .panel { padding: 24px; }
}
@media (max-width: 640px) {
  :root { --gutter: 16px; --header-height: 64px; --anchor-offset: 80px; --toc-offset: 80px; }
  .no-break { white-space: normal; }
  .tilt, [data-tilt] { transform: none; }
  .decor-section > :where(.halo, .stripe-halo, .decor) { max-width: 100%; inset-inline: 0; }
  .topbar-in { gap: 8px; }
  .topbar-end { gap: 6px; margin-left: auto; }
  .brand-en { font-size: 18px; }
  .brand img { width: 24px; height: 24px; }
  .login { padding-inline: 16px; }
  .lang .lang-label { display: none; }
  .grid-2, .grid-5 { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .site-footer { padding-top: 40px; }
  .panel { padding: 20px; }
  .btn { padding-inline: 22px; }
  .footer-bottom { align-items: flex-start; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal, .reveal.pending, .reveal.shown { opacity: 1; transform: none; transition: none; }
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
}