:root { --paper: #f6f3ec; --ink: #1b1915; --muted: #6d665a; --rule: #e1d9c8; --accent: #ff5a1f; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 17px/1.85 "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", sans-serif; }
.top { display: flex; gap: 28px; align-items: center; max-width: 1080px; margin: 0 auto; padding: 40px 24px 24px; }
.cover { width: 150px; border-radius: 6px; box-shadow: 0 12px 30px -12px rgba(0,0,0,.45); }
.book-title { margin: 0; font: 700 40px/1.2 "Songti SC", "STSong", serif; }
.book-sub { margin: 6px 0; color: var(--muted); }
.book-desc { margin: 8px 0 14px; max-width: 42em; }
.btn { display: inline-block; padding: 8px 16px; border-radius: 999px; background: var(--ink); color: var(--paper); text-decoration: none; font-size: 15px; }
.btn.ghost { background: none; color: var(--ink); border: 1px solid var(--rule); }
.layout { display: grid; grid-template-columns: 260px minmax(0, 1fr); gap: 40px; max-width: 1080px; margin: 0 auto; padding: 0 24px 60px; }
.toc { position: sticky; top: 16px; align-self: start; max-height: calc(100vh - 32px); overflow: auto; font-size: 14px; line-height: 1.6; }
.toc-title { font-weight: 700; margin: 0 0 6px; }
.toc ul { list-style: none; padding-left: 0; margin: 0; }
.toc ul ul { padding-left: 1em; color: var(--muted); }
.toc a { text-decoration: none; color: inherit; display: block; padding: 2px 0; }
.toc a:hover { color: var(--accent); }
main { max-width: 42em; }
main h1 { font: 700 30px/1.3 "Songti SC", "STSong", serif; border-top: 1px solid var(--rule); padding-top: 40px; }
footer { text-align: center; color: var(--muted); font-size: 14px; padding: 30px 24px 50px; border-top: 1px solid var(--rule); }
@media (max-width: 820px) {
  .top { flex-direction: column; align-items: flex-start; }
  .layout { grid-template-columns: minmax(0, 1fr); }
  .toc { position: static; max-height: none; }
  main p, main li { text-align: left; }
}
main h1.part { font-size: 36px; color: var(--accent); text-align: left; margin: 60px 0 8px; border-top: 3px solid var(--ink); }
main h1.part + p { text-align: left; color: var(--muted); margin-bottom: 40px; }
main pre { background: #ece5d6; border: 1px solid var(--rule); }
main table { display: block; overflow-x: auto; }
main { min-width: 0; }
main p code, main li code { overflow-wrap: anywhere; }