/* xbe.at: paper, ink, one red. */
:root {
  --paper: #f7f5f0;
  --ink: #1e1c19;
  --muted: #6c675e;
  --rule: #d9d3c7;
  --accent: #9a2e1b;
  --code: #eeeae1;
  --code-ink: #2a2723;
  --serif: Charter, "Bitstream Charter", "Sitka Text", Cambria, "Iowan Old Style", Georgia, serif;
  --sans: -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --paper: #161512;
    --ink: #e6e1d7;
    --muted: #9d968a;
    --rule: #34302a;
    --accent: #e08a68;
    --code: #201e1a;
    --code-ink: #ddd7cb;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 18px/1.6 var(--serif);
  font-kerning: normal;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 2px; }
.wrap { max-width: 46rem; margin: 0 auto; padding: 0 16px; }

/* Masthead */
.masthead { border-bottom: 1px solid var(--rule); }
.masthead-row { display: flex; align-items: baseline; gap: 1.4rem; padding-top: 18px; padding-bottom: 14px; flex-wrap: wrap; }
.mark { font: 600 1.25rem/1 var(--mono); color: var(--ink); letter-spacing: -0.02em; }
.mark:hover { text-decoration: none; color: var(--accent); }
.nav { display: flex; gap: 1.1rem; font: 0.85rem var(--sans); }
.nav a { color: var(--muted); }
.nav a:hover { color: var(--ink); }
.search { margin-left: auto; }
.search input {
  font: 0.85rem var(--sans); color: var(--ink); background: transparent;
  border: 0; border-bottom: 1px solid var(--rule); padding: 4px 0; width: 12rem; border-radius: 0;
}
.search input:focus { outline: none; border-bottom-color: var(--ink); }
.search.big input { width: 100%; font-size: 1.1rem; padding: 8px 0; }
@media (max-width: 560px) {
  .search { margin-left: 0; width: 100%; }
  .search input { width: 100%; }
}

main.wrap { padding-top: 2.4rem; padding-bottom: 3rem; }
h1, h2, h3 { font-family: var(--serif); line-height: 1.25; font-weight: 700; }
h1 { font-size: 2rem; margin: 0 0 0.6rem; letter-spacing: -0.01em; }
.lede { color: var(--muted); font-size: 1.05rem; margin: 0; }
.page-head { margin-bottom: 2rem; }
.crumb { font: 0.8rem var(--sans); color: var(--muted); margin: 0 0 0.6rem; text-transform: uppercase; letter-spacing: 0.06em; }
.crumb a { color: var(--muted); }
.count { font: 0.8rem var(--sans); color: var(--muted); font-weight: 400; }

/* Home: a table of contents */
.intro { margin-bottom: 2.6rem; }
.intro h1 { font-size: 2.3rem; max-width: 32rem; }
.toc { border-top: 2px solid var(--ink); }
.toc-topic { padding: 1rem 0 1.1rem; border-bottom: 1px solid var(--rule); }
.toc-topic h2 { font-size: 1.3rem; margin: 0; display: flex; align-items: baseline; gap: 0.6rem; }
.toc-topic h2 a { color: var(--ink); }
.toc-topic h2 a:hover { color: var(--accent); text-decoration: none; }
.toc-topic h2 .count { margin-left: auto; }
.toc-topic .desc { margin: 0.2rem 0 0; color: var(--muted); font-size: 0.95rem; }
.toc-topic .subs { margin: 0.45rem 0 0; font: 0.82rem/1.7 var(--sans); }
.toc-topic .sep { color: var(--rule); }
.lab-note { margin-top: 2.4rem; }
.lab-note h2 { font: 0.8rem var(--sans); text-transform: uppercase; letter-spacing: 0.08em; color: var(--muted); margin: 0 0 0.3rem; }
.lab-note p { margin: 0; }

/* Lists of notes */
.sections { list-style: none; padding: 0; margin: 0 0 2.2rem; columns: 2; column-gap: 2rem; font: 0.9rem/1.5 var(--sans); }
.sections li { break-inside: avoid; padding: 0.25rem 0; }
@media (max-width: 560px) { .sections { columns: 1; } }
.list-head { font: 0.8rem var(--sans); text-transform: uppercase; letter-spacing: 0.08em; color: var(--muted); margin: 0 0 0.4rem; font-weight: 400; }
.entries { list-style: none; padding: 0; margin: 0; border-top: 1px solid var(--rule); }
.entries li { padding: 0.85rem 0 0.9rem; border-bottom: 1px solid var(--rule); display: grid; grid-template-columns: 1fr auto; column-gap: 1rem; }
.entries li > a { color: var(--ink); font-weight: 600; font-size: 1.02rem; line-height: 1.35; }
.entries li > a:hover { color: var(--accent); text-decoration: none; }
.entries .len { font: 0.78rem var(--sans); color: var(--muted); white-space: nowrap; padding-top: 0.2rem; }
.entries p { grid-column: 1 / -1; margin: 0.25rem 0 0; color: var(--muted); font-size: 0.92rem; line-height: 1.5; }
.entries .place { grid-column: 1 / -1; font: 0.75rem var(--sans); color: var(--muted); margin-top: 0.3rem; text-transform: uppercase; letter-spacing: 0.05em; }

.pager { display: flex; align-items: baseline; justify-content: space-between; gap: 1rem; margin-top: 1.6rem; font: 0.88rem var(--sans); }
.pager .nums { display: flex; gap: 0.15rem; flex-wrap: wrap; justify-content: center; }
.pager .nums a, .pager .nums b, .pager .gap { min-width: 2rem; text-align: center; padding: 0.2rem 0.3rem; }
.pager .nums b { border-bottom: 2px solid var(--ink); }
.pager .off { color: var(--rule); }

/* An article */
.note-head { margin-bottom: 1.6rem; }
.note-head h1 { font-size: 2.1rem; }
.meta { font: 0.82rem var(--sans); color: var(--muted); margin: 0; }
.contents { border-top: 1px solid var(--rule); border-bottom: 1px solid var(--rule); padding: 0.6rem 0; margin-bottom: 2rem; font: 0.9rem/1.55 var(--sans); }
.contents summary { cursor: pointer; color: var(--muted); text-transform: uppercase; letter-spacing: 0.08em; font-size: 0.78rem; }
.contents ol { margin: 0.6rem 0 0.2rem; padding-left: 1.6rem; }
.prose { overflow-wrap: break-word; }
.prose h2 { font-size: 1.35rem; margin: 2.4rem 0 0.6rem; scroll-margin-top: 1rem; }
.prose h3 { font-size: 1.1rem; margin: 1.8rem 0 0.5rem; }
.prose p, .prose ul, .prose ol { margin: 0 0 1rem; }
.prose li { margin: 0.2rem 0; }
.prose code { font: 0.86em var(--mono); background: var(--code); padding: 0.08em 0.3em; border-radius: 2px; }
.prose pre { position: relative; background: var(--code); color: var(--code-ink); padding: 0.9rem 1rem; margin: 0 0 1.3rem; overflow-x: auto; border-left: 3px solid var(--rule); font-size: 0.82rem; line-height: 1.55; }
.prose pre code { background: none; padding: 0; font-size: inherit; }
.prose table { border-collapse: collapse; margin: 0 0 1.3rem; font: 0.88rem var(--sans); display: block; overflow-x: auto; }
.prose th, .prose td { border-bottom: 1px solid var(--rule); padding: 0.4rem 0.8rem 0.4rem 0; text-align: left; }
.prose blockquote { margin: 0 0 1rem; padding-left: 1rem; border-left: 3px solid var(--rule); color: var(--muted); }
.prose img { max-width: 100%; height: auto; }
.prose .math.block { overflow-x: auto; margin: 0 0 1.2rem; }
.copy { position: absolute; top: 0.4rem; right: 0.5rem; font: 0.72rem var(--sans); color: var(--muted); background: none; border: 0; cursor: pointer; padding: 0.2rem 0.3rem; }
.copy:hover { color: var(--ink); }

/* highlight.js tokens, in the same palette */
.hljs-keyword, .hljs-built_in, .hljs-literal, .hljs-type { color: var(--accent); }
.hljs-string, .hljs-regexp { color: #4f6a2e; }
.hljs-number { color: #8a5a12; }
.hljs-comment, .hljs-quote { color: var(--muted); font-style: italic; }
.hljs-title, .hljs-title.function_, .hljs-title.class_ { color: #2c4f7c; }
.hljs-meta, .hljs-attr, .hljs-params { color: inherit; }
@media (prefers-color-scheme: dark) {
  .hljs-string, .hljs-regexp { color: #a9c27a; }
  .hljs-number { color: #d9a85c; }
  .hljs-title, .hljs-title.function_, .hljs-title.class_ { color: #8fb3df; }
}

.turn { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; margin-top: 3rem; padding-top: 1rem; border-top: 2px solid var(--ink); }
.turn a { color: var(--ink); font-weight: 600; line-height: 1.35; }
.turn a:hover { color: var(--accent); text-decoration: none; }
.turn span { display: block; font: 0.75rem var(--sans); color: var(--muted); text-transform: uppercase; letter-spacing: 0.08em; font-weight: 400; margin-bottom: 0.2rem; }
.turn .next { text-align: right; }
.more { margin-top: 2.6rem; }
.more h2 { font: 0.8rem var(--sans); text-transform: uppercase; letter-spacing: 0.08em; color: var(--muted); font-weight: 400; margin: 0 0 0.4rem; }

/* Lab */
.lab { margin: 0; }
.lab dt { font-weight: 600; margin-top: 1rem; }
.lab dd { margin: 0.1rem 0 0; color: var(--muted); }

/* Footer */
.colophon { border-top: 1px solid var(--rule); font: 0.82rem/1.6 var(--sans); color: var(--muted); }
.colophon-row { padding-top: 1.4rem; padding-bottom: 2rem; }
.colophon p { margin: 0 0 0.5rem; }
.colophon .links { display: flex; flex-wrap: wrap; gap: 0.3rem 1rem; }
.colophon a { color: var(--muted); }
.colophon a:hover { color: var(--ink); }
q { quotes: "\201C" "\201D"; }

/* The book */
.book { display: grid; grid-template-columns: 120px 1fr; gap: 1.4rem; align-items: start; border-top: 1px solid var(--rule); border-bottom: 1px solid var(--rule); padding: 1.3rem 0; margin: 0 0 2.6rem; }
.book img { display: block; width: 120px; height: auto; box-shadow: 0 1px 3px rgba(0, 0, 0, 0.18); }
.book p { margin: 0 0 0.4rem; font-size: 0.95rem; }
.book .kicker { font: 0.75rem var(--sans); text-transform: uppercase; letter-spacing: 0.08em; color: var(--muted); }
.book .title { font-size: 1.15rem; font-weight: 700; line-height: 1.3; }
.book .title a { color: var(--ink); }
.book .title a:hover { color: var(--accent); text-decoration: none; }
.book.small { grid-template-columns: 80px 1fr; margin: 2.6rem 0 0; }
.book.small img { width: 80px; }
@media (max-width: 420px) { .book { grid-template-columns: 90px 1fr; gap: 1rem; } .book img { width: 90px; } }