:root {
  color-scheme: light;
  --bg: #fbfaf7;
  --panel: #f3f0ea;
  --text: #22201d;
  --muted: #716b64;
  --line: #ddd7ce;
  --accent: #315a77;
  --code: #ece8e0;
  --shadow: rgba(42, 38, 32, 0.08);
}

[data-theme="dark"] {
  color-scheme: dark;
  --bg: #171817;
  --panel: #202321;
  --text: #e9e5de;
  --muted: #aaa39a;
  --line: #383c39;
  --accent: #8cb9d4;
  --code: #292d2a;
  --shadow: rgba(0, 0, 0, 0.3);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.72 "Noto Serif SC", "Source Han Serif SC", Georgia, serif;
}
a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 3px; }
button { font: inherit; }
.layout { display: grid; grid-template-columns: 260px minmax(0, 760px) 220px; gap: 32px; max-width: 1320px; margin: auto; padding: 28px; }
.sidebar, .toc { position: sticky; top: 28px; align-self: start; max-height: calc(100vh - 56px); overflow: auto; }
.brand { display: block; color: var(--text); font-size: 18px; font-weight: 700; margin-bottom: 20px; text-decoration: none; }
.nav-group { margin: 18px 0; }
.nav-group-title, .toc-title { color: var(--muted); font: 600 12px/1.4 system-ui, sans-serif; letter-spacing: .1em; text-transform: uppercase; }
.nav-group a, .toc a { display: block; padding: 5px 0; color: var(--muted); font: 14px/1.45 system-ui, sans-serif; text-decoration: none; }
.nav-group a:hover, .toc a:hover, .nav-group a.active { color: var(--accent); }
.toolbar { display: flex; gap: 8px; margin: 16px 0; }
.tool-button, .copy-button {
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--panel);
  color: var(--text);
  cursor: pointer;
  font: 13px/1.4 system-ui, sans-serif;
  padding: 5px 8px;
}
main { min-width: 0; }
.article { padding-bottom: 64px; }
.article-meta { border-bottom: 1px solid var(--line); color: var(--muted); margin-bottom: 28px; padding-bottom: 18px; }
.article-meta h1 { color: var(--text); font-size: 34px; line-height: 1.25; margin: 0 0 8px; }
.article h1 { font-size: 30px; margin-top: 1.5em; }
.article h2 { border-bottom: 1px solid var(--line); font-size: 23px; margin-top: 1.8em; padding-bottom: 4px; }
.article h3 { font-size: 19px; margin-top: 1.6em; }
pre { position: relative; overflow-x: auto; border: 1px solid var(--line); border-radius: 8px; background: var(--code); padding: 16px; }
pre .copy-button { position: absolute; right: 8px; top: 8px; opacity: .82; }
code { font-family: "SFMono-Regular", Consolas, monospace; font-size: .88em; }
table { border-collapse: collapse; width: 100%; }
th, td { border: 1px solid var(--line); padding: 7px 10px; text-align: left; }
figure { margin: 24px 0; overflow-x: auto; }
.math { cursor: copy; }
.math-block { display: block; margin: 18px auto; overflow-x: auto; text-align: center; }
.math-inline { display: inline-block; vertical-align: -.22em; }
.math svg { max-width: 100%; }
.toc ol { list-style: none; margin: 8px 0; padding: 0; }
.toc li.depth-3 { padding-left: 12px; }
.toc li.depth-4 { padding-left: 24px; }
#search-panel { border-top: 1px solid var(--line); margin-top: 14px; padding-top: 14px; }
pagefind-searchbox { font-family: system-ui, sans-serif; }
/* PDF 扫描笔记面板 */
.pdf-list {
  display: grid;
  gap: 1.35rem;
}
.pdf-panel {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
}
.pdf-panel-header {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem 0.8rem;
  align-items: baseline;
  justify-content: space-between;
  border-bottom: 1px solid var(--line);
  padding: 0.7rem 0.85rem;
}
.pdf-panel-title {
  margin: 0;
  font-size: 0.98rem;
  font-weight: 650;
}
.pdf-panel-actions {
  display: flex;
  gap: 0.65rem;
  font-size: 0.9rem;
}
.pdf-preview {
  display: block;
  width: 100%;
  height: min(78vh, 820px);
  min-height: 520px;
  border: 0;
  background: var(--panel);
}
@media (max-width: 720px) {
  .pdf-preview {
    height: 72vh;
    min-height: 420px;
  }
}

@media (max-width: 1080px) {
  .layout { grid-template-columns: 230px minmax(0, 1fr); }
  .toc { display: none; }
}
@media (max-width: 760px) {
  .layout { display: block; padding: 18px; }
  .sidebar { position: static; max-height: none; }
  .nav-groups { display: none; }
  .sidebar.open .nav-groups { display: block; }
  .article-meta h1 { font-size: 29px; }
}