:root {
  --bg: #f8f6ef;
  --ink: #1e1d1a;
  --muted: #666257;
  --line: #d8d1bf;
  --link: #175f86;
  --panel: #fffcf5;
  --panel-active: #edf5f9;
  --sans: "IBM Plex Sans", "PingFang SC", "Microsoft YaHei", sans-serif;
  --serif: "Newsreader", "Noto Serif SC", "Source Han Serif SC", serif;
  --mono: "IBM Plex Mono", Consolas, monospace;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  line-height: 1.72;
}

.topbar,
.shell,
.footer {
  width: min(980px, calc(100vw - 44px));
  margin-left: auto;
  margin-right: auto;
}

.topbar {
  margin-top: 24px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
}

.brand {
  color: var(--ink);
  text-decoration: none;
  font-family: var(--serif);
  font-size: clamp(2rem, 4vw, 2.6rem);
  font-weight: 500;
}

.topbar-actions {
  display: flex;
  align-items: center;
  gap: 14px;
}

.nav {
  display: flex;
  gap: 16px;
  align-items: center;
}

.nav-btn,
.nav-link {
  border: 0;
  background: transparent;
  color: var(--muted);
  font: inherit;
  font-size: 1rem;
  font-weight: 600;
  padding: 0;
  line-height: 1;
  cursor: pointer;
  text-decoration: none;
  border-bottom: 1px solid transparent;
}

.nav-btn:hover,
.nav-link:hover,
.nav-btn.active {
  color: var(--ink);
  border-bottom-color: var(--ink);
}

.lang-switch {
  display: inline-flex;
  border: 1px solid var(--line);
  border-radius: 999px;
  overflow: hidden;
}

.lang-btn {
  border: 0;
  background: transparent;
  color: var(--muted);
  font-family: var(--sans);
  font-size: 0.85rem;
  padding: 4px 10px;
  cursor: pointer;
}

.lang-btn.active {
  background: #ece6d5;
  color: var(--ink);
}

.shell {
  margin-top: 24px;
}

.panel {
  display: none;
}

.panel.active {
  display: block;
}

.kicker {
  margin: 0 0 10px;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.82rem;
  letter-spacing: 0.06em;
}

h1,
h2,
h3 {
  margin: 0;
  font-family: var(--serif);
  font-weight: 500;
  line-height: 1.2;
}

h1 {
  font-size: clamp(2.1rem, 6vw, 3.25rem);
  margin-bottom: 16px;
  max-width: 16ch;
}

.lead {
  margin: 0 0 8px;
  color: #3d3a33;
  max-width: 70ch;
  font-size: 1.08rem;
}

.quick-actions {
  margin-top: 16px;
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.jump-btn,
.text-link,
.text-btn {
  border: 0;
  background: transparent;
  color: var(--link);
  font: inherit;
  font-weight: 500;
  font-size: 0.98rem;
  text-decoration: none;
  padding: 0;
  cursor: pointer;
  border-bottom: 1px solid transparent;
}

.jump-btn:hover,
.text-link:hover,
.text-btn:hover {
  border-bottom-color: var(--link);
}

.home-block {
  margin-top: 34px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
}

.home-block h2 {
  font-size: 2rem;
  margin-bottom: 12px;
}

.home-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.home-item {
  padding: 10px 0;
  border-bottom: 1px solid #e3dcc9;
}

.home-entry-link {
  border: 0;
  background: transparent;
  color: var(--ink);
  font-family: var(--serif);
  font-size: 1.45rem;
  text-align: left;
  cursor: pointer;
  padding: 0;
  line-height: 1.3;
}

.home-entry-link:hover {
  color: var(--link);
}

.home-entry-summary {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 0.94rem;
}

.docs-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 12px;
  margin-bottom: 14px;
}

.docs-head h2 {
  font-size: 2.3rem;
  margin-bottom: 4px;
}

.docs-head p {
  margin: 0;
  color: var(--muted);
}

.docs-layout {
  display: grid;
  grid-template-columns: minmax(250px, 300px) minmax(0, 1fr);
  gap: 18px;
  align-items: stretch;
  height: calc(100vh - 230px);
  height: calc(100dvh - 230px);
  min-height: 480px;
}

.doc-sidebar {
  height: 100%;
  max-height: none;
  overflow-y: auto;
  overscroll-behavior: contain;
  padding-right: 14px;
  border-right: 1px solid var(--line);
}

.doc-sidebar h3 {
  margin: 0 0 10px;
  font-size: 1rem;
  letter-spacing: 0.03em;
}

.column-grid,
.doc-list {
  display: grid;
  gap: 8px;
}

.column-grid {
  margin-bottom: 14px;
}

.column-chip,
.doc-item {
  width: 100%;
  border: 1px solid var(--line);
  background: var(--panel);
  border-radius: 8px;
  padding: 8px 10px;
  text-align: left;
  cursor: pointer;
}

.column-chip {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.column-chip span {
  font-size: 0.9rem;
}

.column-chip small {
  font-family: var(--mono);
  color: var(--muted);
  font-size: 0.75rem;
}

.column-chip.active,
.doc-item.active {
  border-color: #9ebed0;
  background: var(--panel-active);
}

.doc-item strong {
  display: block;
  font-size: 0.94rem;
  margin-bottom: 3px;
}

.doc-item small {
  color: var(--muted);
  font-size: 0.82rem;
  line-height: 1.35;
}

.doc-viewer {
  height: 100%;
  overflow-y: auto;
  overscroll-behavior: contain;
  padding-right: 6px;
}

.doc-viewer h1 {
  font-size: 2.35rem;
  margin: 0 0 14px;
}

.doc-viewer h2 {
  font-size: 1.56rem;
  margin: 1.1em 0 0.45em;
}

.doc-viewer h3 {
  font-size: 1.22rem;
  margin: 1em 0 0.45em;
}

.doc-viewer p,
.doc-viewer li,
.doc-viewer blockquote {
  font-size: 1.02rem;
}

.doc-viewer ul {
  padding-left: 1.2em;
}

.doc-viewer a {
  color: var(--link);
}

.doc-viewer code {
  font-family: var(--mono);
  font-size: 0.88em;
  background: #f0ede2;
  border-radius: 4px;
  padding: 0.06em 0.28em;
}

.doc-viewer pre {
  border: 1px solid #d7cfbb;
  border-radius: 10px;
  background: #f5f1e7;
  padding: 12px;
  overflow: auto;
}

.doc-viewer pre code {
  background: transparent;
  padding: 0;
}

.doc-viewer blockquote {
  margin: 1em 0;
  padding: 4px 12px;
  border-left: 3px solid #9fb59f;
  color: #4b4942;
  background: #f8f4eb;
}

.doc-viewer img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  border: 1px solid var(--line);
  margin: 10px 0;
}

.footer {
  margin-top: 26px;
  margin-bottom: 22px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.82rem;
  display: flex;
  justify-content: space-between;
  gap: 10px;
}

.placeholder {
  color: var(--muted);
}

@media (max-width: 860px) {
  .topbar {
    flex-direction: column;
    align-items: flex-start;
  }

  .topbar-actions {
    width: 100%;
    justify-content: space-between;
  }

  .docs-layout {
    grid-template-columns: 1fr;
    height: auto;
    min-height: 0;
  }

  .doc-sidebar {
    height: auto;
    max-height: none;
    border-right: 0;
    border-bottom: 1px solid var(--line);
    padding-right: 0;
    padding-bottom: 14px;
    overflow: visible;
  }

  .doc-viewer {
    height: auto;
    max-height: none;
    overflow: visible;
  }

  .home-entry-link {
    font-size: 1.26rem;
  }

  .footer {
    flex-direction: column;
    align-items: flex-start;
  }
}