/* 《自学是门手艺》阅读版
   设计要点：正文安静，两处承重 —— 箴言引用块（宋体 + 悬挂「）与 In/Out 代码单元 */

:root {
  --paper:      #F7F7F4;
  --sidebar-bg: #F1F1EC;
  --surface:    #FDFDFB;
  --ink:        #1A1A1C;
  --ink-2:      #56565C;
  --ink-3:      #8C8C85;
  --rule:       #E3E3DC;
  --accent:     #17616B;
  --accent-bg:  rgba(23, 97, 107, .09);

  --kw: #9A2C6B;  --str: #1D6B4A;  --com: #90908A;
  --num: #B0561A; --fun: #17616B;  --bui: #2E4A7D;

  --sans:  "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --serif: "Songti SC", "STSong", "Source Han Serif SC", "Noto Serif CJK SC", Georgia, serif;
  --mono:  "SF Mono", ui-monospace, "JetBrains Mono", Menlo, Consolas, monospace;

  --nav-w: 274px;
}

:root[data-theme="dark"] {
  --paper:      #17171A;
  --sidebar-bg: #131316;
  --surface:    #1D1D22;
  --ink:        #E7E6E1;
  --ink-2:      #A3A39B;
  --ink-3:      #74746D;
  --rule:       #2E2E35;
  --accent:     #63B6C0;
  --accent-bg:  rgba(99, 182, 192, .12);

  --kw: #E58AC0;  --str: #7FD0A2;  --com: #6F6F68;
  --num: #E0A46A; --fun: #6FC3CE;  --bui: #93B2E8;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.85;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 3px; }

:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 2px; }

/* ── 阅读进度 ───────────────────────────── */
.progress {
  position: fixed; inset: 0 0 auto 0; height: 2px; z-index: 60;
  background: var(--accent); transform: scaleX(0); transform-origin: 0 50%;
}

/* ── 侧栏目录 ───────────────────────────── */
.sidebar {
  position: fixed; inset: 0 auto 0 0; width: var(--nav-w); z-index: 40;
  display: flex; flex-direction: column;
  background: var(--sidebar-bg); border-right: 1px solid var(--rule);
}

.brand {
  display: block; padding: 26px 24px 20px; text-decoration: none;
  border-bottom: 1px solid var(--rule); color: var(--ink);
}
.brand-t { display: block; font-family: var(--serif); font-size: 18px; font-weight: 700; letter-spacing: .02em; }
.brand-s { display: block; margin-top: 5px; font-size: 11.5px; line-height: 1.5; color: var(--ink-3); }

.nav { flex: 1; overflow-y: auto; padding: 10px 10px 64px; overscroll-behavior: contain; }
.nav-group {
  margin: 20px 14px 7px; font-family: var(--mono);
  font-size: 10px; letter-spacing: .16em; text-transform: uppercase; color: var(--ink-3);
}
.nav-list { margin: 0; padding: 0; list-style: none; }
.nav-list a {
  display: block; padding: 7px 14px; border-radius: 5px;
  font-size: 13.5px; line-height: 1.45; color: var(--ink-2); text-decoration: none;
}
.nav-eb {
  display: block; margin-bottom: 1px;
  font-family: var(--mono); font-size: 9.5px; letter-spacing: .1em; color: var(--ink-3);
}
.nav-list a:hover { background: var(--rule); color: var(--ink); }
.nav-list li.on a { background: var(--accent-bg); color: var(--ink); font-weight: 600; }
.nav-list li.on .nav-eb { color: var(--accent); }

.topbar {
  position: fixed; top: 0; left: var(--nav-w); right: 0; z-index: 50;
  display: flex; justify-content: flex-end; gap: 10px; padding: 13px 20px;
  pointer-events: none;
}
.menu-btn, .theme-btn {
  pointer-events: auto;
  font-family: var(--mono); font-size: 11px; letter-spacing: .08em;
  color: var(--ink-2); background: var(--paper);
  border: 1px solid var(--rule); border-radius: 999px; padding: 6px 13px; cursor: pointer;
}
.menu-btn:hover, .theme-btn:hover { color: var(--ink); border-color: var(--ink-3); }
.menu-btn { display: none; }

.scrim { position: fixed; inset: 0; z-index: 35; background: rgba(0, 0, 0, .38); }

/* ── 正文 ───────────────────────────────── */
.main { margin-left: var(--nav-w); }
.doc { max-width: 41rem; margin: 0 auto; padding: 68px 32px 110px; }

.head { padding-bottom: 1.7rem; margin-bottom: 2.6rem; border-bottom: 1px solid var(--rule); }
.eyebrow {
  margin: 0; font-family: var(--mono);
  font-size: 11.5px; letter-spacing: .16em; color: var(--accent);
}
.head h1 {
  margin: .42em 0 .5em; font-family: var(--serif); font-weight: 700;
  font-size: 34px; line-height: 1.35; letter-spacing: .01em; text-wrap: pretty;
}
.meta { margin: 0; font-size: 12.5px; color: var(--ink-3); font-family: var(--mono); letter-spacing: .03em; }

.doc h2 {
  margin: 3.2rem 0 1.1rem; font-family: var(--serif); font-weight: 700;
  font-size: 25px; line-height: 1.45; text-wrap: pretty;
}
.doc h3 { margin: 2.4rem 0 .9rem; font-size: 19px; font-weight: 600; }
.doc h4 { margin: 2rem 0 .8rem; font-size: 16.5px; font-weight: 600; color: var(--ink-2); }

.doc p { margin: 0 0 1.35em; }
.doc ul, .doc ol { margin: 0 0 1.35em; padding-left: 1.45em; }
.doc li { margin-bottom: .45em; }
.doc li::marker { color: var(--ink-3); }
.doc strong { font-weight: 600; }
.doc hr { height: 0; margin: 3rem 0; border: 0; border-top: 1px solid var(--rule); }

/* 箴言：单段短引用 —— 这本书的骨架 */
blockquote.aphorism {
  position: relative; margin: 2.1rem 0; padding-left: 1.9rem;
  font-family: var(--serif); font-size: 19.5px; line-height: 1.9; color: var(--ink);
}
blockquote.aphorism::before {
  content: "「"; position: absolute; left: -.15rem; top: -.12em;
  font-family: var(--serif); font-size: 30px; line-height: 1; color: var(--accent); opacity: .5;
}
blockquote.aphorism p { margin: 0; }

/* 其余引用块：长引文、列表 */
blockquote:not(.aphorism) {
  margin: 1.9rem 0; padding: .2rem 0 .2rem 1.35rem;
  border-left: 2px solid var(--rule); color: var(--ink-2); font-size: 16px;
}
blockquote:not(.aphorism) > :last-child { margin-bottom: 0; }

/* ── Jupyter In / Out 单元 ──────────────── */
.cell {
  margin: 2.1rem 0; border: 1px solid var(--rule); border-radius: 6px;
  overflow: hidden; background: var(--surface);
}
.cell-bar {
  display: flex; align-items: center; justify-content: space-between;
  padding: 6px 14px; border-bottom: 1px solid var(--rule); background: var(--paper);
  font-family: var(--mono); font-size: 10.5px; letter-spacing: .14em; text-transform: uppercase;
}
.cell-bar-out { border-bottom: 0; border-top: 1px solid var(--rule); }
.cell-tag { color: var(--accent); font-weight: 600; }
.cell-bar-out .cell-tag { color: var(--ink-3); }
.cell-lang { color: var(--ink-3); }

.cell-code { background: var(--surface); }
.cell-out { padding: 16px 14px; background: var(--paper); }
.cell-out > :last-child { margin-bottom: 0; }
.cell-out img { display: block; max-width: 100%; margin: 0 auto; border-radius: 3px; background: #fff; }
.cell-out pre { margin: 0; }

pre {
  margin: 0; padding: 15px 16px; overflow-x: auto;
  font-family: var(--mono); font-size: 13.5px; line-height: 1.72; tab-size: 4;
}
pre code { font-family: inherit; font-size: inherit; }
.cell-out pre, .doc > pre {
  color: var(--ink-2); font-size: 13px; background: var(--surface);
  border-radius: 5px; border: 1px solid var(--rule);
}

code {
  font-family: var(--mono); font-size: .9em;
  background: var(--accent-bg); color: var(--ink);
  padding: 1.5px 5px; border-radius: 3px;
}
pre code, .cell code { background: none; padding: 0; }

/* 语法高亮 */
.kw, .cf                 { color: var(--kw); }
.st, .ch, .vs, .sc, .ss  { color: var(--str); }
.co, .cm, .do            { color: var(--com); font-style: italic; }
.dv, .fl, .bn, .dt       { color: var(--num); }
.fu                      { color: var(--fun); }
.bu, .va, .at, .im       { color: var(--bui); }
.op, .sp                 { color: var(--ink-2); }
.er                      { color: #C2410C; }

/* ── 插图 ───────────────────────────────── */
p.plate { margin: 2.2rem 0; }
p.plate img {
  display: block; max-width: 100%; margin: 0 auto;
  background: #fff; padding: 6px; border: 1px solid var(--rule); border-radius: 5px;
}
:root[data-theme="dark"] p.plate img,
:root[data-theme="dark"] .cell-out img { filter: brightness(.93); }

/* ── 表格 ───────────────────────────────── */
.doc table {
  width: 100%; margin: 2rem 0; border-collapse: collapse;
  font-size: 14.5px; display: block; overflow-x: auto;
}
.doc th {
  padding: 8px 12px; text-align: left; border-bottom: 1.5px solid var(--rule);
  font-family: var(--mono); font-size: 11px; letter-spacing: .1em;
  text-transform: uppercase; color: var(--ink-3); font-weight: 500; white-space: nowrap;
}
.doc td { padding: 8px 12px; border-bottom: 1px solid var(--rule); vertical-align: top; }

/* ── 章末导航 ───────────────────────────── */
.footnav {
  display: flex; justify-content: space-between; gap: 24px;
  margin-top: 4.5rem; padding-top: 2rem; border-top: 1px solid var(--rule);
}
.fn { max-width: 47%; text-decoration: none; color: var(--ink); }
.fn-dir {
  display: block; margin-bottom: 2px;
  font-family: var(--mono); font-size: 10.5px; letter-spacing: .12em; color: var(--ink-3);
}
.fn-t { font-size: 15px; line-height: 1.5; }
.fn:hover .fn-t { color: var(--accent); }
.fn-next { text-align: right; }

/* ── 窄屏 ───────────────────────────────── */
@media (max-width: 900px) {
  body { font-size: 16.5px; }
  .menu-btn { display: block; }
  .topbar {
    left: 0; justify-content: space-between; padding: 9px 14px;
    background: var(--paper); border-bottom: 1px solid var(--rule);
  }
  /* 抽屉从顶栏下方滑出，留出顶栏高度，别让书名被盖住 */
  .sidebar {
    width: min(310px, 84vw); padding-top: 49px;
    transform: translateX(-100%); transition: transform .22s ease;
    box-shadow: 0 0 34px rgba(0, 0, 0, .16);
  }
  .sidebar.open { transform: none; }
  .brand { padding: 20px 22px 16px; }
  .main { margin-left: 0; }
  .doc { padding: 84px 20px 90px; }
  pre { font-size: 12.5px; padding: 13px 14px; }
  .head h1 { font-size: 27px; }
  .doc h2 { font-size: 21px; }
  blockquote.aphorism { font-size: 18px; padding-left: 1.6rem; }
  .footnav { flex-direction: column; gap: 18px; }
  .fn { max-width: 100%; }
  .fn-next { text-align: left; }
}

/* ── 手机分页阅读 ───────────────────────── */
:root.paged, :root.paged body { height: 100%; overflow: hidden; }
:root.paged .main { display: none; }

.pager { position: fixed; inset: 49px 0 34px; overflow: hidden; }
.page {
  position: absolute; inset: 0; padding: 22px 20px 8px;
  overflow: hidden; visibility: hidden; opacity: 0;
  transition: opacity .13s linear;
}
.page.on { visibility: visible; opacity: 1; }
.page.tall { overflow-y: auto; -webkit-overflow-scrolling: touch; }
.page > :first-child { margin-top: 0; }
.page > .head { padding-top: 4px; }

.pagenum {
  position: fixed; left: 0; right: 0; bottom: 0; height: 34px;
  display: flex; align-items: center; justify-content: center;
  font-family: var(--mono); font-size: 11px; letter-spacing: .1em; color: var(--ink-3);
  background: var(--paper); border-top: 1px solid var(--rule);
}
:root.paged .footnav { margin-top: 2.5rem; padding-top: 1.6rem; }

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; }
}

.pagenum.hint { color: var(--accent); }

/* ── 视频嵌入（原书用 Jupyter IFrame 写死 width=800，窄屏会溢出）─ */
iframe {
  display: block; width: 100%; max-width: 100%; aspect-ratio: 16 / 9; height: auto;
  margin: 2rem 0; border: 1px solid var(--rule); border-radius: 6px; background: #000;
}
.cell-out iframe { margin: 0; }

/* ── 首页目录 ───────────────────────────── */
.home { max-width: 44rem; margin: 0 auto; padding: 76px 32px 120px; }
.home-hd { padding-bottom: 2rem; margin-bottom: 1rem; border-bottom: 1px solid var(--rule); }
.home-hd h1 {
  margin: .5rem 0 .4rem; font-family: var(--serif); font-weight: 700;
  font-size: 40px; letter-spacing: .02em;
}
.home-hd .sub { margin: 0; color: var(--ink-2); font-size: 16px; }
.home-hd .stat {
  margin: 1.2rem 0 0; font-family: var(--mono); font-size: 12px;
  letter-spacing: .06em; color: var(--ink-3);
}
.home-grp {
  margin: 2.6rem 0 .8rem; font-family: var(--mono);
  font-size: 11px; letter-spacing: .16em; text-transform: uppercase; color: var(--accent);
}
.home-list { margin: 0; padding: 0; list-style: none; }
.home-list li { border-bottom: 1px solid var(--rule); }
.home-list a {
  display: flex; gap: 14px; align-items: baseline;
  padding: 12px 6px; text-decoration: none; color: var(--ink);
}
.home-list a:hover { background: var(--accent-bg); }
.home-list .n {
  flex: none; width: 7.2em; white-space: nowrap; font-family: var(--mono);
  font-size: 11px; letter-spacing: .06em; color: var(--ink-3);
}
.home-list .t { flex: 1; font-size: 16px; line-height: 1.5; }
.home-list .w { flex: none; font-family: var(--mono); font-size: 11px; color: var(--ink-3); }
@media (max-width: 620px) {
  .home { padding: 74px 20px 90px; }
  .home-hd h1 { font-size: 30px; }
  .home-list .n { width: 6.4em; font-size: 10px; }
  .home-list .w { display: none; }
}

/* ── 兜底：任何位置的图都不许撑破容器 ─────
   （.plate / .cell-out 之外还有正文内联图，之前漏了约束） */
.doc img { max-width: 100%; height: auto; }

/* 行内 code 里有超长无空格串（正则那章的 IP 匹配式 93 字符），
   不给断行机会就会顶破正文列 */
:not(pre) > code { overflow-wrap: anywhere; }
.doc p, .doc li, blockquote { overflow-wrap: break-word; }

/* ── 署名与授权 ─────────────────────────── */
.credit {
  max-width: 41rem; margin: 0 auto; padding: 2.2rem 32px 3rem;
  border-top: 1px solid var(--rule); font-size: 12.5px; line-height: 1.75; color: var(--ink-3);
}
.credit p { margin: 0 0 .35em; }
.credit strong { color: var(--ink-2); font-weight: 600; }
.credit a { color: var(--ink-2); }
.home .credit { max-width: 44rem; margin-top: 3.5rem; padding-left: 0; padding-right: 0; }
@media (max-width: 900px) { .credit { padding: 2rem 20px 2.5rem; } }