:root {
  color-scheme: light;
  --paper: #f7f7f2;
  --paper-2: #f3f4ee;
  --ink: #232820;
  --muted: #62675d;
  --line: #daddd1;
  --green: #426441;
  --green-deep: #304d30;
  --green-pale: #e9eee1;
  --code: #eef1e8;
  --sans: "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Microsoft YaHei", sans-serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --header: 4.25rem;
  --sidebar: 16.5rem;
  --toc: 14rem;
  --measure: 40rem;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--header) + 1rem); }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; }
a { color: inherit; }
button, input { font: inherit; color: inherit; }
button { cursor: pointer; }
:focus-visible { outline: 2px solid var(--green); outline-offset: 3px; }
::selection { background: #d2dfc3; }
.skip {
  position: fixed;
  top: -4rem;
  left: 1rem;
  z-index: 80;
  padding: 0.6rem 0.8rem;
  background: var(--ink);
  color: #fff;
}
.skip:focus { top: 0.6rem; }

.header {
  position: sticky;
  top: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  height: var(--header);
  padding: 0 1.25rem;
  background: color-mix(in srgb, var(--paper) 92%, transparent);
  border-bottom: 1px solid transparent;
  backdrop-filter: blur(10px);
}
.header.is-scrolled { border-bottom-color: var(--line); }
.menu-button, .icon-button {
  display: none;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  padding: 0;
  border: 1px solid var(--line);
  background: var(--paper);
}
.drawer-head .icon-button, .search-head .icon-button { display: inline-flex; }
.menu-button svg, .icon-button svg { width: 1.1rem; height: 1.1rem; }
.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  color: inherit;
  text-decoration: none;
  font-weight: 600;
  letter-spacing: -0.04em;
  font-size: 1.05rem;
}
.brand img { width: 1.6rem; height: 1.6rem; }
.brand-docs {
  color: var(--muted);
  font-weight: 500;
  letter-spacing: 0;
  font-size: 0.82rem;
}
.search-button {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  min-width: min(28rem, 46vw);
  margin-left: auto;
  padding: 0.45rem 0.7rem;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--muted);
  text-align: left;
}
.search-button span { flex: 1; font-size: 0.92rem; }
kbd {
  font-family: var(--mono);
  font-size: 0.72rem;
  border: 1px solid var(--line);
  padding: 0.05rem 0.35rem;
  color: var(--muted);
  background: var(--paper);
}
.header-tools {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  margin-left: 1rem;
}
.lang {
  display: inline-flex;
  border: 1px solid var(--line);
  background: var(--paper);
}
.lang a {
  padding: 0.28rem 0.55rem;
  color: var(--muted);
  text-decoration: none;
  font-size: 0.78rem;
}
.lang a[aria-current="true"] { background: var(--green-pale); color: var(--green-deep); }
.header-tools a.quiet {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.82rem;
}
.header-tools a.quiet:hover { color: var(--green); }

.page-title {
  margin: 0;
  font-weight: 450;
  letter-spacing: -0.045em;
  line-height: 1.05;
}
html[lang="zh-CN"] body { line-height: 1.75; }
html[lang="zh-CN"] .page-title,
html[lang="zh-CN"] .prose h2,
html[lang="zh-CN"] .prose h3 { letter-spacing: 0; }

.shell {
  max-width: 80rem;
  margin: 0 auto;
  display: grid;
  grid-template-columns: var(--sidebar) minmax(0, 1fr);
  gap: 2rem;
  padding: 2.25rem 1.5rem 4rem;
}
.shell:has(.toc) { grid-template-columns: var(--sidebar) minmax(0, 1fr) var(--toc); }
.sidebar { position: sticky; top: calc(var(--header) + 1rem); align-self: start; max-height: calc(100vh - var(--header) - 2rem); overflow: auto; }
.nav-section { margin: 0 0 1.6rem; }
.nav-section h2 {
  margin: 0 0 0.45rem;
  font-size: 0.92rem;
  font-weight: 600;
  letter-spacing: -0.02em;
}
.nav-section ul { list-style: none; margin: 0; padding: 0 0 0 0.8rem; border-left: 1px solid var(--line); }
.nav-section a {
  position: relative;
  display: block;
  padding: 0.28rem 0 0.28rem 0.75rem;
  color: var(--muted);
  text-decoration: none;
  font-size: 0.92rem;
  line-height: 1.45;
}
.nav-section a:hover { color: var(--ink); }
.nav-section a[aria-current="page"] { color: var(--green); font-weight: 600; }
.nav-section a[aria-current="page"]::before {
  content: "";
  position: absolute;
  left: -0.23rem;
  top: 0.72rem;
  width: 0.38rem;
  height: 0.38rem;
  border-radius: 50%;
  background: var(--green);
}
.nav-fallback { display: none; margin: 0 1.25rem; }

.content { min-width: 0; }
.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.35rem 0.45rem;
  margin: 0 0 0.85rem;
  color: var(--muted);
  font-size: 0.82rem;
}
.crumbs a { color: var(--green-deep); text-decoration: none; }
.crumbs a:hover { text-decoration: underline; }
.crumbs [aria-current="page"] { color: var(--ink); }
.page-kicker { margin: 0 0 0.35rem; color: var(--green); font-size: 0.86rem; font-weight: 600; }
.page-title { font-size: clamp(2rem, 3vw, 2.6rem); margin-bottom: 1.25rem; }
.prose { max-width: var(--measure); }
.prose > :first-child { margin-top: 0; }
.prose h2, .prose h3 { letter-spacing: -0.03em; line-height: 1.25; font-weight: 560; scroll-margin-top: calc(var(--header) + 1rem); }
.prose h2 { font-size: 1.45rem; margin: 2.2rem 0 0.7rem; }
.prose h3 { font-size: 1.12rem; margin: 1.6rem 0 0.45rem; }
.heading-link {
  margin-left: 0.35rem;
  color: var(--green);
  text-decoration: none;
  opacity: 0;
  font-weight: 500;
}
.prose h2:hover .heading-link,
.prose h3:hover .heading-link,
.heading-link:focus { opacity: 1; }
@media (hover: none) {
  .heading-link { opacity: 0.45; }
}
.prose p, .prose li { color: #3a4036; }
.prose a { color: var(--green-deep); text-underline-offset: 0.18em; }
.prose ul, .prose ol { padding-left: 1.2rem; }
.prose li { margin: 0.3rem 0; }
.prose li::marker { color: var(--green); }
.note {
  margin: 1.2rem 0;
  padding: 0.85rem 1rem;
  border-left: 3px solid var(--green);
  background: var(--green-pale);
}
.note p { margin: 0.3rem 0; }
.table-wrap { overflow-x: auto; margin: 1rem 0 1.4rem; border: 1px solid var(--line); }
table { width: 100%; border-collapse: collapse; font-size: 0.92rem; line-height: 1.5; }
th, td { text-align: left; vertical-align: top; padding: 0.65rem 0.75rem; border-bottom: 1px solid var(--line); }
th { background: var(--paper-2); font-weight: 600; }
tr:last-child td { border-bottom: 0; }
code {
  font-family: var(--mono);
  font-size: 0.86em;
  background: var(--code);
  padding: 0.08em 0.32em;
}
pre { margin: 0; }
pre code { background: none; padding: 0; font-size: 0.84rem; line-height: 1.7; }
.code-block {
  position: relative;
  margin: 1rem 0 1.3rem;
  background: #fbfbf8;
  border: 1px solid var(--line);
  overflow: auto;
}
.code-block pre { padding: 0.95rem 1rem 1rem; }
.code-copy {
  position: absolute;
  top: 0.45rem;
  right: 0.45rem;
  border: 1px solid var(--line);
  background: var(--paper);
  color: var(--muted);
  font-size: 0.72rem;
  padding: 0.2rem 0.45rem;
}
.code-label {
  display: block;
  padding: 0.35rem 0.8rem 0;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.04em;
  color: var(--muted);
}
.figure { margin: 1.2rem 0 1.5rem; }
.figure img { display: block; border: 1px solid var(--line); background: #fff; }
.figure figcaption { margin-top: 0.45rem; color: var(--muted); font-size: 0.82rem; }

.toc { position: sticky; top: calc(var(--header) + 1.5rem); align-self: start; }
.toc h2 { margin: 0 0 0.6rem; font-size: 0.78rem; letter-spacing: 0.08em; text-transform: uppercase; color: var(--muted); font-weight: 600; }
.toc ol { list-style: none; margin: 0; padding: 0; }
.toc a { display: block; padding: 0.22rem 0; color: var(--muted); text-decoration: none; font-size: 0.84rem; line-height: 1.4; }
.toc a:hover, .toc a.is-active { color: var(--green); }
.toc .toc-h3 { padding-left: 0.75rem; }

.pager {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.8rem;
  margin-top: 2.5rem;
  max-width: var(--measure);
}
.pager a {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  padding: 0.9rem 1rem;
  border: 1px solid var(--line);
  text-decoration: none;
  min-height: 4.4rem;
}
.pager a:hover { border-color: var(--green); background: var(--green-pale); }
.pager .next { text-align: right; align-items: flex-end; grid-column: 2; }
.pager span { color: var(--muted); font-size: 0.75rem; }
.page-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem 1.2rem;
  margin-top: 1.6rem;
  color: var(--muted);
  font-size: 0.82rem;
}
.page-meta a, .page-meta button { color: var(--green-deep); }
.page-meta button {
  border: 0;
  background: none;
  padding: 0;
  font: inherit;
  font-size: inherit;
  cursor: pointer;
}

.page-footer {
  border-top: 1px solid var(--line);
  padding: 1.4rem 1.5rem 2rem;
  display: flex;
  justify-content: flex-start;
  gap: 1.2rem;
  flex-wrap: wrap;
  color: var(--muted);
  font-size: 0.85rem;
  max-width: 80rem;
  margin: 0 auto;
}
.page-footer a { color: inherit; }

.drawer, .scrim, .search-dialog { display: none; }
html.js .drawer.is-open, html.js .search-dialog.is-open { display: block; }
html.js .scrim.is-open { display: block; position: fixed; inset: 0; background: #23282066; z-index: 50; }
.drawer {
  position: fixed;
  z-index: 60;
  inset: 0 auto 0 0;
  width: min(20rem, 88vw);
  background: var(--paper);
  border-right: 1px solid var(--line);
  overflow: auto;
  padding: 1rem 1rem 2rem;
}
.drawer-head, .search-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 0.8rem; }
.search-dialog {
  position: fixed;
  z-index: 70;
  left: 50%;
  top: 12vh;
  transform: translateX(-50%);
  width: min(38rem, calc(100vw - 1.5rem));
  background: #fff;
  border: 1px solid var(--line);
  box-shadow: 0 18px 50px #23282022;
}
.search-head { padding: 0.7rem 0.8rem 0; }
.search-dialog input {
  width: 100%;
  border: 0;
  border-bottom: 1px solid var(--line);
  padding: 0.7rem 1rem 0.9rem;
  background: transparent;
  font-size: 1rem;
}
.search-dialog input:focus { outline: none; }
.search-list { list-style: none; margin: 0; padding: 0.35rem; max-height: min(24rem, 50vh); overflow: auto; }
.search-list button {
  width: 100%;
  text-align: left;
  border: 0;
  background: transparent;
  padding: 0.55rem 0.7rem;
}
.search-list button.is-active, .search-list button:hover { background: var(--green-pale); }
.search-list small { display: block; color: var(--muted); font-size: 0.75rem; }
.search-status { margin: 0; padding: 0.8rem 1rem 1rem; color: var(--muted); font-size: 0.9rem; }
.mobile-toc { display: none; }

@media (max-width: 1100px) {
  .shell { grid-template-columns: var(--sidebar) minmax(0, 1fr); }
  .toc { display: none; }
  .mobile-toc { display: block; margin: 0 0 1.2rem; border: 1px solid var(--line); padding: 0.6rem 0.8rem; }
  .mobile-toc summary { cursor: pointer; color: var(--muted); font-size: 0.86rem; }
  .mobile-toc ol { margin: 0.5rem 0 0; }
}
@media (max-width: 860px) {
  body { font-size: 16px; }
  .header { padding: 0 0.8rem; }
  .search-button { display: none; }
  html.js .menu-button, html.js .search-icon { display: inline-flex; }
  .header-tools { margin-left: auto; gap: 0.45rem; }
  .header-tools a.quiet { display: none; }
  .shell { display: block; padding: 1.25rem 1rem 3rem; }
  .sidebar { display: none; }
  html:not(.js) .nav-fallback { display: block; margin-top: 0.8rem; }
  html:not(.js) .nav-fallback summary { cursor: pointer; padding: 0.7rem 0; }
  .pager { grid-template-columns: 1fr; }
  .pager .next { grid-column: auto; text-align: left; align-items: flex-start; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; }
}
@media print {
  .header, .sidebar, .toc, .mobile-toc, .nav-fallback, .page-footer, .pager, .code-copy, .heading-link, .drawer, .scrim, .search-dialog { display: none !important; }
  .shell { display: block; padding: 0; }
  .content { max-width: none; }
  body { background: #fff; }
  a { text-decoration: underline; }
}