:root {
  --ink: #1b211f;
  --muted: #68756f;
  --paper: #fffdf7;
  --line: #d8d0c0;
  --code-bg: #101816;
  --code-panel: #17231f;
  --code-fg: #f6ead4;
  --code-muted: #a9b8ac;
  --code-add: #1f3d2b;
  --code-add-line: #4eba72;
  --code-mod: #473718;
  --code-mod-line: #e2aa35;
  --tok-comment: #8fa397;
  --tok-keyword: #f29f67;
  --tok-type: #79d6c2;
  --tok-string: #d8c06f;
  --tok-number: #a7c77d;
  --tok-preproc: #df8f8f;
  --accent: #0b6f5f;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: Georgia, "Times New Roman", serif;
}

.book {
  width: min(860px, calc(100% - 36px));
  margin: 0 auto;
  padding: 56px 0 96px;
}

.book-nav {
  margin-bottom: 38px;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.9rem;
}

.book-nav a {
  color: var(--accent);
}

h1 {
  margin: 0 0 24px;
  font-size: clamp(2.8rem, 8vw, 5.8rem);
  line-height: 0.96;
  letter-spacing: 0;
}

.book-author {
  margin: -8px 0 28px;
  color: var(--muted);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.95rem;
  line-height: 1.45;
}

.book-author a {
  color: var(--accent);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.18em;
}

h2 {
  margin-top: 58px;
  padding-top: 28px;
  border-top: 1px solid var(--line);
  font-size: 2.25rem;
}

h3 {
  margin-top: 34px;
  font-size: 1.45rem;
}

p,
li {
  font-size: 1.06rem;
  line-height: 1.78;
}

a {
  color: var(--accent);
}

.code-block {
  margin: 30px 0;
  overflow: hidden;
  border: 1px solid #2a4f45;
  border-radius: 10px;
  background: var(--code-bg);
  box-shadow: 0 14px 36px rgba(19, 32, 29, 0.14);
}

.code-block.is-modified {
  border-color: #7b6130;
}

.code-title {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 16px;
  margin: 0;
  padding: 11px 16px;
  border-bottom: 1px solid rgba(246, 234, 212, 0.12);
  background: linear-gradient(90deg, #1d302a, #14211d);
  color: var(--code-fg);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.78rem;
  line-height: 1.35;
}

.code-note {
  color: var(--code-muted);
  text-align: right;
}

pre {
  margin: 0;
  overflow-x: auto;
  padding: 16px 0;
  background: var(--code-panel);
  color: var(--code-fg);
  font-size: 0.88rem;
  line-height: 1.6;
  tab-size: 4;
  -webkit-overflow-scrolling: touch;
}

pre > code {
  display: block;
  padding: 0 18px;
}

.code-line {
  display: block;
  min-height: 1.55em;
  margin: 0 -18px;
  padding: 0 18px;
  border-left: 3px solid transparent;
}

.code-line:empty {
  min-height: 0.65em;
}

.code-line:empty + .code-line:empty {
  display: none;
}

.code-line.is-modified,
.code-line.line-mark {
  border-left-color: var(--code-mod-line);
  background: var(--code-mod);
}

.code-line.is-added,
.code-line.line-add {
  border-left-color: var(--code-add-line);
  background: var(--code-add);
}

.tok-comment {
  color: var(--tok-comment);
  font-style: italic;
}

.tok-keyword {
  color: var(--tok-keyword);
}

.tok-type {
  color: var(--tok-type);
}

.tok-string {
  color: var(--tok-string);
}

.tok-number {
  color: var(--tok-number);
}

.tok-preproc {
  color: var(--tok-preproc);
}

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}

p code,
li code {
  padding: 0.1em 0.28em;
  border-radius: 4px;
  background: #ece5d6;
}

figure {
  margin: 36px 0;
}

.book figure:not(.code-block) {
  overflow: visible;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #fffaf0;
  box-shadow: 0 12px 34px rgba(72, 58, 35, 0.08);
}

.book figure:not(.code-block) img {
  display: block;
  width: 100%;
  border: 0;
  border-radius: 8px;
}

.book figure:not(.code-block) img[src*="/diagrams/"] {
  width: 100%;
  max-width: 100%;
  margin-left: 0;
  border-radius: 6px;
}

figcaption {
  margin: 10px 2px 2px;
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.6;
}

.callout {
  padding: 18px 20px;
  border-left: 4px solid var(--accent);
  background: #eef5ef;
}

@media print {
  .book-nav {
    display: none;
  }

  body {
    background: white;
  }

  .book {
    width: auto;
    padding: 0;
  }

  h2 {
    break-before: page;
  }
}

@media (max-width: 640px) {
  .book {
    width: min(100% - 24px, 860px);
    padding-top: 32px;
  }

  h1 {
    font-size: clamp(2.35rem, 13vw, 3.7rem);
  }

  h2 {
    font-size: 1.85rem;
  }

  p,
  li {
    font-size: 1rem;
  }

  .code-title {
    gap: 6px;
  }

  .code-note {
    width: 100%;
    text-align: left;
  }

  pre {
    font-size: 0.8rem;
  }

  .book figure:not(.code-block) {
    padding: 8px;
  }

  .book figure:not(.code-block) img[src*="/diagrams/"] {
    width: 100%;
    margin-left: 0;
  }
}