/* PyGTK Notebook -- a plain, book-like reading style. No external assets. */

:root {
  --ink: #1c1a17;
  --ink-soft: #5b554d;
  --paper: #fbf9f4;
  --paper-raised: #ffffff;
  --rule: #ddd6c8;
  --accent: #8a4b2a;
  --accent-soft: #f2e7de;
  --code-bg: #f3efe6;
  --measure: 38rem;
  --serif: Georgia, "Iowan Old Style", "Palatino Linotype", Palatino, serif;
  --sans: "Helvetica Neue", Arial, system-ui, sans-serif;
  --mono: "SFMono-Regular", Menlo, Consolas, "DejaVu Sans Mono", monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --ink: #e6e1d8;
    --ink-soft: #a49c8f;
    --paper: #16150f;
    --paper-raised: #1e1d16;
    --rule: #3a372c;
    --accent: #e0a273;
    --accent-soft: #2a251c;
    --code-bg: #201f18;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 1.0625rem/1.65 var(--serif);
  -webkit-text-size-adjust: 100%;
}

a { color: var(--accent); }
a:hover { text-decoration: none; }

.skip {
  position: absolute;
  left: -9999px;
}
.skip:focus {
  left: 1rem;
  top: 1rem;
  background: var(--paper-raised);
  padding: 0.5rem 0.75rem;
  z-index: 10;
}

/* ---------- chrome ---------- */

.masthead {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
  align-items: baseline;
  justify-content: space-between;
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--rule);
  font-family: var(--sans);
  font-size: 0.875rem;
}

.masthead-title {
  font-weight: 700;
  letter-spacing: 0.02em;
  text-decoration: none;
  color: var(--ink);
}

.masthead-nav a {
  margin-left: 1.25rem;
  text-decoration: none;
}
.masthead-nav a:first-child { margin-left: 0; }

.colophon {
  border-top: 1px solid var(--rule);
  margin-top: 4rem;
  padding: 1.5rem;
  color: var(--ink-soft);
  font-family: var(--sans);
  font-size: 0.8125rem;
}
.colophon p { max-width: var(--measure); margin: 0 auto; }

main {
  max-width: calc(var(--measure) + 3rem);
  margin: 0 auto;
  padding: 2.5rem 1.5rem 0;
}

/* ---------- home ---------- */

.hero {
  border-bottom: 1px solid var(--rule);
  padding-bottom: 2rem;
  margin-bottom: 2rem;
}
.hero h1 {
  font-size: clamp(2.25rem, 7vw, 3.25rem);
  line-height: 1.1;
  margin: 0.25rem 0 0.5rem;
}
.tagline {
  font-size: 1.125rem;
  color: var(--ink-soft);
  margin: 0 0 0.25rem;
}
.byline {
  font-family: var(--sans);
  font-size: 0.875rem;
  color: var(--ink-soft);
  margin: 0 0 1.5rem;
}

.eyebrow {
  font-family: var(--sans);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-soft);
  margin: 0;
}

.button {
  display: inline-block;
  font-family: var(--sans);
  font-size: 0.875rem;
  text-decoration: none;
  padding: 0.55rem 1.1rem;
  border: 1px solid var(--accent);
  background: var(--accent);
  color: var(--paper);
  border-radius: 2px;
}
.button-quiet {
  background: transparent;
  color: var(--accent);
}
.hero-actions { display: flex; gap: 0.75rem; flex-wrap: wrap; margin: 0; }

.intro { margin-bottom: 2.5rem; }

.part { margin-top: 2.75rem; }
.part-title {
  font-size: 1.35rem;
  margin: 0 0 0.35rem;
  line-height: 1.25;
}
.part-title span {
  display: block;
  font-family: var(--sans);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.2rem;
}
.part-blurb {
  color: var(--ink-soft);
  font-size: 0.95rem;
  margin: 0 0 1rem;
}

.contents {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--rule);
}
.contents-item { border-bottom: 1px solid var(--rule); }
.contents-item a {
  display: flex;
  gap: 1rem;
  align-items: baseline;
  padding: 0.7rem 0.25rem;
  text-decoration: none;
  color: var(--ink);
}
.contents-item a:hover { background: var(--accent-soft); }
.contents-number {
  font-family: var(--sans);
  font-size: 0.8125rem;
  color: var(--ink-soft);
  min-width: 1.75rem;
  text-align: right;
}
.contents-title { flex: 1; }
.is-appendix .contents-title { color: var(--ink-soft); }

/* ---------- chapter ---------- */

.chapter-header {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--rule);
}
.chapter-header h1 {
  font-size: clamp(1.9rem, 5.5vw, 2.6rem);
  line-height: 1.15;
  margin: 0.35rem 0 0;
}

.toc {
  background: var(--paper-raised);
  border: 1px solid var(--rule);
  border-radius: 3px;
  padding: 1rem 1.25rem;
  margin-bottom: 2.5rem;
  font-family: var(--sans);
  font-size: 0.875rem;
}
.toc-title {
  margin: 0 0 0.5rem;
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-soft);
}
.toc ul { margin: 0; padding-left: 1.1rem; }
.toc li { margin: 0.2rem 0; }
.toc a { text-decoration: none; }
.toc a:hover { text-decoration: underline; }
.toc:not(:has(li)) { display: none; }

.prose h2 {
  font-size: 1.55rem;
  margin: 2.75rem 0 0.75rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--rule);
}
.prose h3 { font-size: 1.25rem; margin: 2rem 0 0.5rem; }
.prose h4 { font-size: 1.05rem; margin: 1.5rem 0 0.5rem; }
.prose p { margin: 0 0 1.15rem; }
.prose ul, .prose ol { margin: 0 0 1.15rem; padding-left: 1.4rem; }
.prose li { margin: 0.25rem 0; }

.prose dt {
  font-family: var(--mono);
  font-size: 0.9em;
  margin-top: 0.9rem;
}
.prose dd { margin: 0.15rem 0 0 1.25rem; }

.prose blockquote {
  margin: 1.5rem 0;
  padding: 0.75rem 1rem;
  border-left: 3px solid var(--rule);
  color: var(--ink-soft);
  font-size: 0.95em;
}
.prose blockquote p:last-child { margin-bottom: 0; }

.prose img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 1.5rem 0;
  border: 1px solid var(--rule);
  background: var(--paper-raised);
}

.prose code {
  font-family: var(--mono);
  font-size: 0.875em;
  background: var(--code-bg);
  padding: 0.1em 0.3em;
  border-radius: 2px;
}

.prose pre {
  background: var(--code-bg);
  border: 1px solid var(--rule);
  border-radius: 3px;
  padding: 0.9rem 1rem;
  overflow-x: auto;
  font-size: 0.8125rem;
  line-height: 1.55;
  margin: 0 0 1.5rem;
}
.prose pre code {
  background: none;
  padding: 0;
  font-size: 1em;
}

.prose hr {
  border: 0;
  border-top: 1px solid var(--rule);
  margin: 2.5rem 0;
}

.footnotes {
  margin-top: 3rem;
  padding-top: 1rem;
  border-top: 1px solid var(--rule);
  font-size: 0.9rem;
  color: var(--ink-soft);
}

/* ---------- pager ---------- */

.pager {
  display: flex;
  gap: 1rem;
  justify-content: space-between;
  margin-top: 3.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--rule);
  font-family: var(--sans);
  font-size: 0.9375rem;
}
.pager a {
  display: block;
  max-width: 48%;
  text-decoration: none;
}
.pager-next { margin-left: auto; text-align: right; }
.pager span {
  display: block;
  font-size: 0.6875rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

/* ---------- syntax highlighting (rouge) ---------- */

.highlight .c, .highlight .c1, .highlight .cm, .highlight .cs { color: #8a8677; font-style: italic; }
.highlight .k, .highlight .kn, .highlight .kd, .highlight .kc { color: #8a4b2a; font-weight: 600; }
.highlight .s, .highlight .s1, .highlight .s2, .highlight .sb, .highlight .sd { color: #40693f; }
.highlight .nf, .highlight .nc { color: #2f5d7c; }
.highlight .nb { color: #6b4e8a; }
.highlight .m, .highlight .mi, .highlight .mf { color: #9a5b12; }
.highlight .o, .highlight .p { color: var(--ink-soft); }

@media (prefers-color-scheme: dark) {
  .highlight .c, .highlight .c1, .highlight .cm, .highlight .cs { color: #7e7767; }
  .highlight .k, .highlight .kn, .highlight .kd, .highlight .kc { color: #e0a273; }
  .highlight .s, .highlight .s1, .highlight .s2, .highlight .sb, .highlight .sd { color: #9cc48e; }
  .highlight .nf, .highlight .nc { color: #8ab4d8; }
  .highlight .nb { color: #c4a2e0; }
  .highlight .m, .highlight .mi, .highlight .mf { color: #d8ab6e; }
}

@media print {
  .masthead, .pager, .toc, .colophon, .skip { display: none; }
  body { background: #fff; color: #000; font-size: 11pt; }
  main { max-width: none; padding: 0; }
}