/* Public course pages (/learn). Same "commit log" look as the landing page:
   navy ground, signal orange accent, Gloock / Schibsted Grotesk / IBM Plex Mono. */
:root {
  --paper: #0A1628;
  --paper-2: #0F2038;
  --ink: #EAF2FF;
  --ink-2: #94A3B8;
  --rule: rgba(148, 178, 222, 0.08);
  --rule-strong: rgba(148, 178, 222, 0.2);
  --signal: #FF6A26;
  --signal-ink: #0A1628;
  --signal-soft: rgba(255, 106, 38, 0.1);
  --code-bg: #060F1C;
  --f-display: "Gloock", "Bodoni 72", Didot, Georgia, serif;
  --f-body: "Schibsted Grotesk", "Helvetica Neue", Arial, sans-serif;
  --f-mono: "IBM Plex Mono", ui-monospace, Menlo, Consolas, monospace;
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 400 17px/1.65 var(--f-body);
  -webkit-font-smoothing: antialiased;
}
a { color: var(--signal); text-underline-offset: 3px; }
.mono { font-family: var(--f-mono); font-size: 0.78rem; letter-spacing: 0.02em; color: var(--ink-2); text-transform: lowercase; }
.wrap { max-width: 1180px; margin: 0 auto; padding: 0 24px; }
.narrow { max-width: 820px; }

/* header */
.top { border-bottom: 1px solid var(--rule-strong); background: var(--paper); position: sticky; top: 0; z-index: 10; }
.top-in { display: flex; align-items: center; justify-content: space-between; height: 60px; gap: 16px; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--ink); text-decoration: none; font-size: 1.1rem; }
.brand b { font-weight: 700; }
.brand i { font-style: normal; color: var(--signal); }
.nav { display: flex; align-items: center; gap: 22px; }
.nav a { color: var(--ink-2); text-decoration: none; font-size: 0.95rem; }
.nav a:hover { color: var(--ink); }

.btn, .nav a.btn {
  display: inline-block; background: var(--signal); color: var(--signal-ink);
  font-weight: 600; text-decoration: none; padding: 9px 16px; border-radius: 4px;
  box-shadow: 0 0 0 0 var(--ink); transition: transform .12s ease, box-shadow .12s ease;
  white-space: nowrap;
}
.btn:hover, .nav a.btn:hover { color: var(--signal-ink); transform: translate(-2px, -2px); box-shadow: 3px 3px 0 0 var(--ink); }
.btn-ghost { display: inline-block; color: var(--ink); text-decoration: none; padding: 9px 16px; border: 1px solid var(--rule-strong); border-radius: 4px; }
.btn-ghost:hover { border-color: var(--ink-2); }

/* headings */
h1, h2, h3, h4 { line-height: 1.2; }
h1, h2 { font-family: var(--f-display); font-weight: 400; letter-spacing: -0.01em; }
h1 { font-size: clamp(2rem, 4vw, 3rem); margin: 0.2em 0 0.4em; }
h1 em { font-style: italic; color: var(--signal); }
.eyebrow { margin: 0; }
.lede { font-size: 1.15rem; color: var(--ink-2); max-width: 62ch; }

/* breadcrumb */
.crumbs ol { list-style: none; display: flex; flex-wrap: wrap; gap: 6px; padding: 0; margin: 28px 0 8px; font-family: var(--f-mono); font-size: 0.78rem; color: var(--ink-2); }
.crumbs li + li::before { content: "/"; margin-right: 6px; opacity: .5; }
.crumbs a { color: var(--ink-2); text-decoration: none; }
.crumbs a:hover { color: var(--signal); }

/* module lists */
.mods { list-style: none; padding: 0; margin: 0; }
.mods li a { display: block; padding: 6px 10px; color: var(--ink); text-decoration: none; border-left: 2px solid transparent; font-size: 0.95rem; }
.mods li a:hover { color: var(--signal); border-left-color: var(--rule-strong); }
.mods li a[aria-current="page"] { color: var(--signal); border-left-color: var(--signal); background: var(--signal-soft); }
.mods .grp > span { display: block; padding: 12px 10px 4px; font-family: var(--f-mono); font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--ink-2); }
.mods .grp ol { list-style: none; padding: 0 0 0 10px; margin: 0; }

/* index */
.hero { padding: 56px 0 24px; border-bottom: 1px solid var(--rule-strong); }
.sec { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.4fr); gap: 32px; padding: 36px 0; border-bottom: 1px solid var(--rule); }
.sec-head h2 { margin: 6px 0 10px; font-size: 1.8rem; }
.sec-head h2 a { color: var(--ink); text-decoration: none; }
.sec-head h2 a:hover { color: var(--signal); }
.sec-head p:last-child { color: var(--ink-2); margin: 0; }
.toc { margin: 24px 0; border-top: 1px solid var(--rule-strong); padding-top: 12px; }

/* module page */
.doc { display: grid; grid-template-columns: 270px minmax(0, 1fr); gap: 48px; }
.side { position: sticky; top: 60px; align-self: start; max-height: calc(100vh - 60px); overflow-y: auto; padding: 24px 0 32px; }
.side-box summary { cursor: pointer; list-style: none; font-weight: 600; padding: 0 10px 12px; border-bottom: 1px solid var(--rule-strong); margin-bottom: 8px; }
.side-box summary::-webkit-details-marker { display: none; }
.side-box summary .mono { display: block; font-weight: 400; }
.side-all { display: block; padding: 14px 10px 0; font-size: 0.9rem; text-decoration: none; }
.main { min-width: 0; max-width: 780px; padding-bottom: 64px; }

/* rendered markdown */
.prose { overflow-wrap: break-word; }
.prose h1 { margin-top: 0.3em; }
.prose h2 { font-size: 1.75rem; margin: 2em 0 0.6em; padding-top: 0.6em; border-top: 1px solid var(--rule-strong); }
.prose h3 { font-size: 1.25rem; font-weight: 600; margin: 1.8em 0 0.5em; }
.prose h4 { font-size: 1.05rem; font-weight: 600; margin: 1.5em 0 0.4em; }
.prose p, .prose ul, .prose ol { margin: 0 0 1em; }
.prose li { margin: 0.25em 0; }
.prose strong { color: #fff; font-weight: 600; }
.prose hr { border: 0; border-top: 1px solid var(--rule); margin: 2em 0; }
.prose hr + h2 { border-top: 0; padding-top: 0; margin-top: 0; }
.prose blockquote { margin: 1.4em 0; padding: 4px 18px; border-left: 3px solid var(--signal); background: var(--signal-soft); color: var(--ink); }
.prose code { font-family: var(--f-mono); font-size: 0.86em; background: var(--paper-2); border: 1px solid var(--rule); padding: 1px 5px; border-radius: 3px; }
.prose pre { background: var(--code-bg); border: 1px solid var(--rule-strong); border-radius: 4px; padding: 16px 18px; overflow-x: auto; line-height: 1.5; margin: 1.2em 0; }
.prose pre code, .prose pre code.hljs { background: none; border: 0; padding: 0; font-size: 0.84rem; }
.table-wrap { overflow-x: auto; margin: 1.2em 0; }
.prose table { border-collapse: collapse; width: 100%; font-size: 0.92rem; }
.prose th, .prose td { border: 1px solid var(--rule-strong); padding: 8px 10px; text-align: left; vertical-align: top; }
.prose th { background: var(--paper-2); font-weight: 600; }

/* pager + cta */
.pager { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin: 48px 0 32px; }
.pager a { display: block; padding: 14px 16px; border: 1px solid var(--rule-strong); border-radius: 4px; text-decoration: none; color: var(--ink); }
.pager a:hover { border-color: var(--signal); }
.pager small { display: block; font-family: var(--f-mono); font-size: 0.72rem; color: var(--ink-2); }
.pager .next { text-align: right; }
.cta { margin: 40px 0 56px; padding: 26px 28px; border: 1px solid var(--rule-strong); border-left: 3px solid var(--signal); background: var(--paper-2); border-radius: 4px; }
.cta h2 { margin: 4px 0 8px; font-size: 1.7rem; border: 0; padding: 0; }
.cta p { color: var(--ink-2); margin: 0 0 16px; }
.cta-k { font-family: var(--f-mono); font-size: 0.75rem; margin: 0 !important; }
.cta-row { display: flex; flex-wrap: wrap; gap: 12px; }

/* footer */
.foot { border-top: 1px solid var(--rule-strong); padding: 24px 0 32px; font-size: 0.85rem; color: var(--ink-2); }
.foot-in { display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.foot nav { display: flex; gap: 18px; }
.foot a { color: var(--ink-2); text-decoration: none; }
.foot a:hover { color: var(--ink); }

@media (max-width: 900px) {
  .doc { grid-template-columns: 1fr; gap: 0; }
  .side { position: static; max-height: none; overflow: visible; padding: 16px 0 0; order: 2; border-top: 1px solid var(--rule-strong); }
  .sec { grid-template-columns: 1fr; gap: 12px; }
}
@media (max-width: 600px) {
  .wrap { padding: 0 16px; }
  .hide-sm { display: none; }
  .nav { gap: 14px; }
  .nav a.btn { padding: 7px 12px; font-size: 0.85rem; }
  .pager { grid-template-columns: 1fr; }
  .pager .next { text-align: left; }
  body { font-size: 16px; }
}
@media (prefers-reduced-motion: reduce) {
  .btn, .nav a.btn { transition: none; }
}