:root {
  --max-content: 820px;
  --toc-width: 260px;
}

html[data-theme="light"] {
  --bg: #ffffff;
  --bg-soft: #f6f8fa;
  --fg: #1f2328;
  --fg-muted: #59636e;
  --border: #d1d9e0;
  --link: #0969da;
  --topbar-bg: #ffffffee;
  --code-bg: #f6f8fa;
  --table-stripe: #f6f8fa;
}

html[data-theme="dark"] {
  --bg: #0d1117;
  --bg-soft: #161b22;
  --fg: #e6edf3;
  --fg-muted: #9198a1;
  --border: #30363d;
  --link: #4493f8;
  --topbar-bg: #0d1117ee;
  --code-bg: #161b22;
  --table-stripe: #161b22;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.7;
}

a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Topbar */
.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  gap: 12px;
  height: 52px;
  padding: 0 18px;
  background: var(--topbar-bg);
  backdrop-filter: saturate(180%) blur(6px);
  border-bottom: 1px solid var(--border);
}
.brand {
  font-weight: 600;
  color: var(--fg);
  letter-spacing: .5px;
}
.doc-title {
  flex: 1;
  color: var(--fg-muted);
  font-size: 14px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg-soft);
  color: var(--fg);
  cursor: pointer;
}
.theme-toggle:hover { border-color: var(--link); }

/* Layout: TOC + content */
.layout {
  display: grid;
  grid-template-columns: var(--toc-width) minmax(0, 1fr);
  gap: 32px;
  max-width: calc(var(--max-content) + var(--toc-width) + 64px);
  margin: 0 auto;
  padding: 28px 24px 80px;
}
.toc {
  position: sticky;
  top: 72px;
  align-self: start;
  max-height: calc(100vh - 96px);
  overflow-y: auto;
  font-size: 14px;
}
.toc-title {
  font-weight: 600;
  color: var(--fg-muted);
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: .08em;
  font-size: 12px;
}
.toc ul { list-style: none; margin: 0; padding: 0; }
.toc li { margin: 2px 0; }
.toc a { color: var(--fg-muted); display: block; padding: 2px 0; line-height: 1.4; }
.toc a:hover { color: var(--link); text-decoration: none; }
.toc-l1 { padding-left: 0; font-weight: 600; }
.toc-l2 { padding-left: 0; }
.toc-l3 { padding-left: 14px; }
.toc-l4 { padding-left: 28px; }
.toc-l5, .toc-l6 { padding-left: 42px; }

.content { min-width: 0; max-width: var(--max-content); }

/* Markdown body */
.markdown-body h1, .markdown-body h2, .markdown-body h3,
.markdown-body h4, .markdown-body h5, .markdown-body h6 {
  margin: 1.6em 0 .6em;
  line-height: 1.3;
  font-weight: 600;
}
.markdown-body h1 { font-size: 1.9em; padding-bottom: .3em; border-bottom: 1px solid var(--border); }
.markdown-body h2 { font-size: 1.5em; padding-bottom: .3em; border-bottom: 1px solid var(--border); }
.markdown-body h3 { font-size: 1.25em; }
.markdown-body h4 { font-size: 1.05em; }
.markdown-body > :first-child { margin-top: 0; }
.markdown-body p { margin: 0 0 1em; }
.markdown-body ul, .markdown-body ol { padding-left: 1.6em; margin: 0 0 1em; }
.markdown-body li { margin: .25em 0; }
.markdown-body blockquote {
  margin: 0 0 1em;
  padding: .2em 1em;
  color: var(--fg-muted);
  border-left: 4px solid var(--border);
}
.markdown-body img { max-width: 100%; border-radius: 6px; }
.markdown-body hr { border: none; border-top: 1px solid var(--border); margin: 2em 0; }

/* Inline code */
.markdown-body code {
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  font-size: .88em;
  background: var(--code-bg);
  padding: .15em .4em;
  border-radius: 6px;
}
/* Highlighted code blocks (chroma) and mermaid */
.markdown-body pre {
  margin: 0 0 1em;
  padding: 14px 16px;
  overflow: auto;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--code-bg);
  font-size: 13.5px;
  line-height: 1.55;
}
.markdown-body pre code { background: none; padding: 0; font-size: inherit; }
.markdown-body pre.chroma { padding: 14px 16px; }
.markdown-body pre.mermaid {
  text-align: center;
  border: 1px solid var(--border);
  background: var(--bg-soft);
}

/* Tables */
.markdown-body table {
  border-collapse: collapse;
  margin: 0 0 1em;
  display: block;
  overflow-x: auto;
  width: max-content;
  max-width: 100%;
}
.markdown-body th, .markdown-body td {
  border: 1px solid var(--border);
  padding: 6px 13px;
}
.markdown-body tr:nth-child(2n) { background: var(--table-stripe); }

/* Task lists */
.markdown-body input[type="checkbox"] { margin-right: .4em; }

/* Mobile: stack and hide TOC */
@media (max-width: 860px) {
  .layout { grid-template-columns: 1fr; padding: 20px 16px 60px; }
  .toc { display: none; }
}

/* Admin */
.admin-wrap { max-width: 960px; margin: 0 auto; padding: 28px 24px 80px; }
.admin-head { display: flex; align-items: center; justify-content: space-between; }
.admin-head h1 { font-size: 1.5em; font-weight: 600; margin: 8px 0 20px; }
.admin-table { width: 100%; border-collapse: collapse; font-size: 14px; }
.admin-table th, .admin-table td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--border); }
.admin-table th { color: var(--fg-muted); font-weight: 600; font-size: 12px; text-transform: uppercase; letter-spacing: .05em; }
.admin-table th.num, .admin-table td.num { text-align: right; font-variant-numeric: tabular-nums; }
.admin-table code { background: var(--code-bg); padding: .1em .4em; border-radius: 6px; font-size: .9em; }
.admin-empty { color: var(--fg-muted); }
.admin-btn { font: inherit; cursor: pointer; border: 1px solid var(--border); background: var(--bg-soft); color: var(--fg); padding: 5px 12px; border-radius: 8px; }
.admin-btn:hover { border-color: var(--link); }
.admin-btn.primary { background: var(--link); border-color: var(--link); color: #fff; }
.admin-btn.danger:hover { border-color: #cf222e; color: #cf222e; }
.admin-login { max-width: 360px; margin: 12vh auto 0; }
.admin-login h1 { font-size: 1.5em; font-weight: 600; margin-bottom: 16px; }
.admin-login label { display: block; font-size: 14px; color: var(--fg-muted); margin-bottom: 14px; }
.admin-login input { display: block; width: 100%; box-sizing: border-box; margin-top: 6px; padding: 9px 12px; font: inherit; border: 1px solid var(--border); border-radius: 8px; background: var(--bg); color: var(--fg); }
.admin-login input:focus { outline: none; border-color: var(--link); }
.admin-error { color: #cf222e; font-size: 14px; margin-bottom: 12px; }