:root {
  --bg: #FFFFFF;
  --bg-panel: #F8F7F5;
  --bg-panel-2: #F1EFEB;
  --border: #E8E6E1;
  --accent: #B4532A;
  --accent-dark: #8A3D1E;
  --text: #1C1B19;
  --text-muted: #6B6862;
  --success: #2F9E6E;
  --warn: #C98A12;
  --error: #D14343;
  --tint-cream: #FFF3D1;
  --tint-mint: #E2F5EC;
  --tint-blue: #E5EDFA;
  --tint-lilac: #EFE8FA;
  --edge-cream: color-mix(in srgb, var(--tint-cream), var(--text) 9%);
  --edge-mint: color-mix(in srgb, var(--tint-mint), var(--text) 8%);
  --edge-blue: color-mix(in srgb, var(--tint-blue), var(--text) 8%);
  --edge-lilac: color-mix(in srgb, var(--tint-lilac), var(--text) 8%);
  --ink-cream: color-mix(in srgb, var(--tint-cream), var(--text) 68%);
  --ink-mint: color-mix(in srgb, var(--tint-mint), var(--text) 66%);
  --ink-blue: color-mix(in srgb, var(--tint-blue), var(--text) 64%);
  --ink-lilac: color-mix(in srgb, var(--tint-lilac), var(--text) 64%);
  --accent-wash: color-mix(in srgb, var(--accent) 8%, var(--bg));
  --accent-line: color-mix(in srgb, var(--accent) 35%, var(--border));
  --veil: rgb(28 27 25 / .18);
  --clear: transparent;
  --font-display: 'Inter', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', system-ui, sans-serif;
  --font-body: 'Inter', 'Noto Sans SC', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, 'SFMono-Regular', Menlo, Consolas, monospace;
  --fs-tiny: 10.5px;
  --fs-code-small: 11.5px;
  --fs-xs: 12px;
  --fs-small: 12.5px;
  --fs-ui: 13px;
  --fs-lang: 13.5px;
  --fs-nav: 14.5px;
  --fs-sm: 14px;
  --fs-button: 15px;
  --fs-body: 16px;
  --fs-brand: 17px;
  --fs-lead: 20px;
  --fs-h3: 22px;
  --fs-h2: clamp(24px, 3vw, 30px);
  --fs-h1: clamp(34px, 4.2vw + 8px, 48px);
  --fs-h1-mobile: clamp(24px, 5vw, 30px);
  --weight-regular: 400;
  --weight-medium: 500;
  --weight-semibold: 600;
  --weight-bold: 700;
  --weight-display: 800;
  --r-xl: 28px;
  --r-lg: 24px;
  --r-float: 20px;
  --r-md: 14px;
  --r-sm: 10px;
  --r-xs: 7px;
  --r-dot: 3px;
  --r-pill: 999px;
  --r-circle: 50%;
  --shadow-hair: 0 1px 2px rgb(28 27 25 / .06);
  --shadow-soft: 0 1px 2px rgb(28 27 25 / .04), 0 10px 24px -12px rgb(28 27 25 / .12);
  --shadow-float: 0 1px 2px rgb(28 27 25 / .05), 0 14px 30px -14px rgb(28 27 25 / .16), 0 34px 64px -30px rgb(28 27 25 / .18);
  --shadow-win: 0 1px 2px rgb(28 27 25 / .05), 0 22px 44px -20px rgb(28 27 25 / .16), 0 56px 96px -36px rgb(28 27 25 / .22), 0 100px 150px -70px rgb(28 27 25 / .20);
  --shadow-btn: 0 1px 0 rgb(255 255 255 / .12) inset, 0 8px 18px -8px rgb(28 27 25 / .45);
  --shadow-ground: rgb(28 27 25 / .14);
  --gutter: 32px;
  --content-width: 1320px;
  --reading-width: 800px;
  --head-width: 1280px;
  --head-height: 68px;
  --section-space: 96px;
  --ease: 150ms ease;
  --reveal-duration: 550ms;
}
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 28px; }
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: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img, svg { display: block; max-width: 100%; }
svg, .dot, .more-dot { flex-shrink: 0; }
img { height: auto; }
a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: .2em; }
button, input, select, textarea { font: inherit; }
button, summary { cursor: pointer; }
button { color: var(--text); }
button:disabled { cursor: not-allowed; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 4px; }
[hidden] { display: none !important; }
h1, h2, h3 {
  font-family: var(--font-display);
  font-weight: var(--weight-display);
  line-height: 1.25;
  letter-spacing: -.02em;
  text-wrap: balance;
  overflow-wrap: break-word;
}
h1 { font-size: var(--fs-h1); line-height: 1.12; }
h2 { font-size: var(--fs-h2); }
h3 { font-size: var(--fs-h3); }
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: 20px;
  background: var(--bg-panel);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  font-size: var(--fs-sm);
  line-height: 1.7;
}
pre code { overflow-wrap: normal; word-break: normal; white-space: pre; }
hr { border: 0; border-top: 1px solid var(--border); margin-block: 32px; }
.wrap { width: 100%; max-width: var(--content-width); margin-inline: auto; padding-inline: var(--gutter); }
.reading { width: 100%; max-width: calc(var(--reading-width) + var(--gutter) * 2); margin-inline: auto; padding-inline: var(--gutter); }
.grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 24px; }
.grid > *, .head-row > *, .footer-grid > *, .object-index > *, .opt-grid > * { min-width: 0; }
.stack > * + * { margin-top: 24px; }
.section { position: relative; padding-top: var(--section-space); padding-bottom: var(--section-space); }
.section--panel { background: var(--bg-panel); color: var(--text); }
.decorated { position: relative; overflow-x: clip; }
.section-head { max-width: 640px; margin: 0 auto 40px; text-align: center; }
.section-head h2 { margin: 0; }
.section-head p { margin: 12px 0 0; color: var(--text-muted); }
.eyebrow { display: inline-block; margin-bottom: 12px; font: var(--weight-semibold) var(--fs-xs)/1.5 var(--font-mono); color: var(--accent); letter-spacing: .02em; }
.keep { white-space: nowrap; }
.muted { color: var(--text-muted); }
.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: absolute; left: var(--gutter); top: -100px; z-index: 100; padding: 12px 18px; background: var(--bg); color: var(--accent); border-radius: var(--r-md); }
.skip-link:focus { top: 8px; }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  min-height: 48px;
  padding: 11px 24px;
  max-width: 100%;
  border: 1px solid var(--clear);
  border-radius: var(--r-pill);
  font-family: var(--font-body);
  font-size: var(--fs-button);
  font-weight: var(--weight-semibold);
  line-height: 1.5;
  letter-spacing: -.005em;
  text-align: center;
  text-decoration: none;
  transition: background-color var(--ease), border-color var(--ease), box-shadow var(--ease), color var(--ease);
}
.btn svg { width: 17px; height: 17px; fill: none; stroke: currentColor; stroke-width: 1.9; stroke-linecap: round; stroke-linejoin: round; }
.btn--ink { background: var(--text); color: var(--bg); box-shadow: var(--shadow-btn); }
.btn--ink:hover, .btn--ink.is-hover { background: var(--accent-dark); color: var(--bg); }
.btn--line { background: var(--bg); color: var(--text); border-color: var(--border); box-shadow: var(--shadow-hair); }
.btn--line:hover, .btn--line.is-hover { border-color: var(--accent-line); color: var(--accent); }
.btn--quiet { background: var(--clear); color: var(--accent); }
.btn:active, .btn.is-active { box-shadow: var(--shadow-hair); }
.btn:disabled, .btn[aria-disabled="true"] { background: var(--bg-panel-2); color: var(--text-muted); border-color: var(--border); box-shadow: none; }
.btn.is-focus { outline: 2px solid var(--accent); outline-offset: 4px; }
.button-row { display: flex; align-items: center; flex-wrap: wrap; gap: 12px; }
.card, .panel { padding: 28px; border: 1px solid var(--border); border-radius: var(--r-lg); background: var(--bg); color: var(--text); box-shadow: var(--shadow-soft); }
.panel { border-radius: var(--r-xl); box-shadow: var(--shadow-float); }
.card h3, .panel h3 { margin-top: 0; }
.card p:last-child, .panel p:last-child { margin-bottom: 0; }
.card-link { display: block; height: 100%; color: inherit; text-decoration: none; }
.card-link:hover { border-color: var(--accent-line); }
.prose { min-width: 0; line-height: 1.85; }
.prose h2 { margin-top: 64px; margin-bottom: 20px; }
.prose h3 { margin-top: 32px; }
.prose p, .prose ul, .prose ol { margin-bottom: 24px; }
.prose li + li { margin-top: 8px; }
.prose :not(pre) > code { padding: 2px 5px; border-radius: var(--r-xs); background: var(--bg-panel); color: var(--text); font-size: .9em; }
.reveal { opacity: 1; transform: none; }
.reveal-pending .reveal:not(.shown) { opacity: 0; transform: translateY(12px); }
.reveal-pending .reveal { transition: opacity var(--reveal-duration) ease, transform var(--reveal-duration) ease; }
.reveal.shown { opacity: 1; transform: none; }

/* 页头使用独立宽版心。 */
.site-head { position: relative; z-index: 40; background: var(--bg); color: var(--text); border-bottom: 1px solid var(--border); }
.head-row {
  position: relative;
  width: 100%;
  max-width: min(100%, calc(var(--head-width) + var(--gutter) * 2));
  margin-inline: auto;
  padding-inline: var(--gutter);
  height: 67px;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 24px;
}
.brand { justify-self: start; display: inline-flex; align-items: center; gap: 10px; color: var(--text); text-decoration: none; font-family: var(--font-display); font-size: var(--fs-brand); font-weight: var(--weight-display); letter-spacing: -.015em; flex-shrink: 0; }
.brand-mark { width: 32px; height: 32px; flex-shrink: 0; }
.nav { min-width: 0; }
.nav ul { display: flex; align-items: center; list-style: none; margin: 0; padding: 0; gap: 2px; }
.nav li { flex-shrink: 0; }
.nav-link, .more > summary {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  height: 38px;
  padding: 0 14px;
  border-radius: var(--r-pill);
  color: var(--text-muted);
  font-size: var(--fs-nav);
  font-weight: var(--weight-medium);
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--ease), background-color var(--ease);
}
.nav-link:hover, .more > summary:hover { background: var(--bg-panel); color: var(--text); }
.nav-link[aria-current="page"], .more-item[aria-current="page"] b, .more.has-current > summary { color: var(--accent); font-weight: var(--weight-semibold); }
.nav-link[aria-current="page"]::after { content: ""; position: absolute; left: 14px; right: 14px; bottom: 4px; height: 2px; border-radius: var(--r-pill); background: var(--accent); }
.more { position: relative; }
.more > summary { list-style: none; }
.more > summary::-webkit-details-marker { display: none; }
.chev { width: 12px; height: 12px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.more[open] > summary { background: var(--bg-panel); color: var(--text); }
.more[open] .chev { transform: rotate(180deg); }
.more-menu { position: absolute; top: calc(100% + 10px); left: 50%; width: 248px; padding: 8px; transform: translateX(-50%); border: 1px solid var(--border); border-radius: var(--r-float); background: var(--bg); color: var(--text); box-shadow: var(--shadow-float); }
.more-item { display: flex; align-items: flex-start; gap: 11px; padding: 10px 12px; min-height: 44px; border-radius: var(--r-md); color: var(--text); text-decoration: none; }
.more-item:hover { background: var(--bg-panel); color: var(--text); }
.more-dot { width: 10px; height: 10px; margin-top: 6px; border: 1px solid var(--border); border-radius: var(--r-dot); }
.more-dot--cream { background: var(--tint-cream); border-color: var(--edge-cream); }
.more-dot--mint { background: var(--tint-mint); border-color: var(--edge-mint); }
.more-dot--lilac { background: var(--tint-lilac); border-color: var(--edge-lilac); }
.more-item b { display: block; font-size: var(--fs-sm); font-weight: var(--weight-semibold); line-height: 1.4; }
.more-item small { display: block; font-size: var(--fs-xs); line-height: 1.4; color: var(--text-muted); }
.head-tools { justify-self: end; 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: 36px; padding: 7px 14px; border: 1px solid var(--border); border-radius: var(--r-pill); background: var(--bg); color: var(--text-muted); font-size: var(--fs-lang); font-weight: var(--weight-medium); white-space: nowrap; }
.lang:hover { color: var(--text); border-color: var(--accent-line); }
.globe { width: 15px; height: 15px; fill: none; stroke: currentColor; stroke-width: 1.5; stroke-linecap: round; }
.lang-short { display: none; }
.language-menu { position: absolute; top: calc(100% + 10px); right: 0; width: 180px; padding: 8px; border: 1px solid var(--border); border-radius: var(--r-float); box-shadow: var(--shadow-float); background: var(--bg); color: var(--text); }
.language-menu a { display: flex; align-items: center; min-height: 44px; padding: 8px 12px; border-radius: var(--r-sm); color: var(--text); text-decoration: none; }
.language-menu a:hover { background: var(--bg-panel); color: var(--accent); }
.language-menu [aria-current="true"] { color: var(--accent); font-weight: var(--weight-semibold); }
.menu-toggle { display: none; place-items: center; min-width: 44px; min-height: 44px; padding: 10px; border: 1px solid var(--border); border-radius: var(--r-pill); background: var(--bg); color: var(--text); }
.menu-toggle svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; }
.mobile-drawer { display: none; }
.nav-veil { position: fixed; inset: var(--head-height) 0 0; z-index: 35; border: 0; background: var(--veil); color: var(--text); }
.site-footer { padding-top: 64px; padding-bottom: 28px; border-top: 1px solid var(--border); background: var(--bg-panel); color: var(--text); }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1.4fr 1fr; gap: 40px; }
.footer-brand p { max-width: 300px; margin: 16px 0 0; font-size: var(--fs-sm); color: var(--text-muted); }
.footer-title { margin: 0 0 14px; font-size: var(--fs-sm); font-weight: var(--weight-semibold); }
.footer-links { list-style: none; margin: 0; padding: 0; }
.footer-links a { display: inline-block; padding-block: 6px; font-size: var(--fs-sm); color: var(--text-muted); text-decoration: none; }
.footer-links a:hover { color: var(--accent); text-decoration: underline; }
.footer-links a[aria-current] { color: var(--accent); }
.copyright { margin-top: 40px; padding-top: 24px; border-top: 1px solid var(--border); font-size: var(--fs-xs); color: var(--text-muted); }
@media (max-width: 1024px) {
  .head-row { display: flex; gap: 12px; }
  .head-row > .nav { display: none; }
  .head-tools { margin-left: auto; }
  .menu-toggle { display: grid; }
  .mobile-drawer:not([hidden]) {
    display: block;
    position: absolute;
    top: 100%;
    inset-inline: 0;
    padding: 16px var(--gutter) 24px;
    max-height: calc(100dvh - var(--head-height));
    overflow-y: auto;
    overscroll-behavior: contain;
    background: var(--bg);
    color: var(--text);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-soft);
  }
  .mobile-drawer ul { margin: 0; padding: 0; list-style: none; }
  .mobile-drawer a { display: flex; align-items: center; width: 100%; min-height: 46px; padding: 11px 14px; border-radius: var(--r-sm); color: var(--text); text-decoration: none; }
  .mobile-drawer a:hover, .mobile-drawer a[aria-current] { background: var(--accent-wash); color: var(--accent); }
  .drawer-label { margin: 16px 14px 6px; font-size: var(--fs-xs); color: var(--text-muted); }
}
@media (max-width: 900px) {
  .grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 768px) {
  h1, .hero-title { font-size: var(--fs-h1-mobile); }
}
@media (max-width: 640px) {
  :root { --gutter: 18px; --section-space: 64px; }
  .grid, .footer-grid { grid-template-columns: minmax(0, 1fr); }
  .brand { font-size: var(--fs-sm); gap: 7px; }
  .brand-mark { width: 28px; height: 28px; }
  .head-row { gap: 8px; }
  .head-tools { margin-left: auto; gap: 6px; }
  .lang { padding-inline: 10px; min-height: 44px; }
  .lang-full { display: none; }
  .lang-short { display: inline; }
  .lang .globe { display: none; }
  .card, .panel { padding: 22px; }
  .tilt, [data-tilt] { transform: none !important; }
  .footer-grid { gap: 28px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
  .reveal-pending .reveal:not(.shown) { opacity: 1; transform: none; }
}