:root {
  --bg: #f2eee5;
  --paper: #fbf8f1;
  --ink: #1f1a17;
  --muted: #6f645a;
  --line: #d8cbbb;
  --accent: #8b3a24;
  --accent-soft: #e7d8c9;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: Georgia, "Songti SC", "Noto Serif SC", serif;
  color: var(--ink);
  background:
    radial-gradient(circle at top left, rgba(139,58,36,0.08), transparent 32%),
    linear-gradient(180deg, #efe7d8 0%, var(--bg) 100%);
}
.layout {
  display: grid;
  grid-template-columns: 300px minmax(0, 1fr);
  min-height: 100vh;
}
.sidebar {
  position: sticky;
  top: 0;
  align-self: start;
  height: 100vh;
  overflow: auto;
  padding: 24px 18px 32px;
  border-right: 1px solid var(--line);
  background: rgba(251,248,241,0.88);
  backdrop-filter: blur(8px);
}
.sidebar-title {
  font-size: 1.25rem;
  font-weight: 700;
}
.sidebar-subtitle {
  margin-top: 6px;
  color: var(--muted);
  font-size: 0.92rem;
}
.toc {
  margin-top: 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.toc a {
  color: var(--ink);
  text-decoration: none;
  padding: 6px 8px;
  border-radius: 8px;
  line-height: 1.35;
}
.toc a:hover {
  background: var(--accent-soft);
}
.toc .zh {
  display: block;
  color: var(--muted);
  font-size: 0.85rem;
  margin-top: 2px;
}
.content {
  padding: 40px min(6vw, 64px) 64px;
}
.hero {
  max-width: 820px;
  margin-bottom: 28px;
}
.hero h1 {
  margin: 0 0 10px;
  font-size: clamp(2rem, 4vw, 3.2rem);
}
.hero p {
  margin: 0;
  color: var(--muted);
  font-size: 1rem;
}
.block {
  max-width: 820px;
  margin-bottom: 18px;
  scroll-margin-top: 24px;
}
.heading {
  margin-top: 36px;
  padding-top: 12px;
  border-top: 1px solid var(--line);
}
.heading h2, .heading h3, .heading h4, .heading h5, .heading h6 {
  margin: 0 0 8px;
}
.heading .zh {
  color: var(--accent);
  font-weight: 700;
}
.pair {
  background: rgba(251,248,241,0.7);
  border: 1px solid rgba(216,203,187,0.8);
  border-radius: 14px;
  padding: 16px 18px;
}
.en, .zh {
  white-space: pre-wrap;
  line-height: 1.8;
}
.en {
  font-size: 1.02rem;
}
.zh {
  margin-top: 10px;
  color: #312924;
}
.meta {
  margin-top: 8px;
  font-size: 0.78rem;
  color: var(--muted);
}
@media (max-width: 920px) {
  .layout {
    grid-template-columns: 1fr;
  }
  .sidebar {
    position: static;
    height: auto;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }
  .content {
    padding: 24px 18px 48px;
  }
}