/* course.css — shared stylesheet for the Zero Architecture course.
   Tufte-inspired: readable serif body, generous margins, restrained color. */

:root {
  --ink: #1a1a1a;
  --paper: #fffff8;
  --muted: #6b6b63;
  --rule: #d8d8cf;
  --accent: #34607a;
  --code-bg: #f4f4ee;
  --warn: #8a5a00;
  --ok: #2f6b3a;
  --maxw: 46rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --ink: #e8e8e0; --paper: #1b1b19; --muted: #9a9a90;
    --rule: #3a3a35; --accent: #7fb0cc; --code-bg: #26261f;
    --warn: #d1a24a; --ok: #7fc48b;
  }
}

* { box-sizing: border-box; }

html { font-size: 18px; }

body {
  background: var(--paper);
  color: var(--ink);
  font-family: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
  line-height: 1.55;
  max-width: var(--maxw);
  margin: 3rem auto 6rem;
  padding: 0 1.4rem;
  -webkit-font-smoothing: antialiased;
}

.eyebrow {
  font-family: ui-sans-serif, system-ui, sans-serif;
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 0.4rem;
}

h1 { font-size: 2rem; line-height: 1.15; margin: 0 0 1.2rem; font-weight: 600; }
h2 {
  font-size: 1.28rem; margin: 2.4rem 0 0.6rem; font-weight: 600;
  padding-bottom: 0.2rem; border-bottom: 1px solid var(--rule);
}
h3 { font-size: 1.05rem; margin: 1.6rem 0 0.4rem; font-weight: 600; }

p, li { font-size: 1.02rem; }
a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 2px; }

code {
  font-family: "SF Mono", "JetBrains Mono", "Fira Code", ui-monospace, monospace;
  font-size: 0.86em;
  background: var(--code-bg);
  padding: 0.1em 0.35em;
  border-radius: 4px;
}

pre {
  background: var(--code-bg);
  border: 1px solid var(--rule);
  border-radius: 8px;
  padding: 1rem 1.1rem;
  overflow-x: auto;
  font-size: 0.82rem;
  line-height: 1.5;
}
pre code { background: none; padding: 0; font-size: inherit; }

blockquote {
  margin: 1.2rem 0;
  padding: 0.4rem 0 0.4rem 1.1rem;
  border-left: 3px solid var(--accent);
  color: var(--muted);
  font-style: italic;
}

/* citation chip → link to a real file:line in the repo */
.cite {
  font-family: ui-monospace, monospace;
  font-size: 0.74rem;
  background: transparent;
  border: 1px solid var(--rule);
  border-radius: 999px;
  padding: 0.05em 0.55em;
  color: var(--muted);
  white-space: nowrap;
  text-decoration: none;
}
.cite:hover { border-color: var(--accent); color: var(--accent); }

.callout {
  border: 1px solid var(--rule);
  border-left: 4px solid var(--accent);
  border-radius: 6px;
  padding: 0.8rem 1rem;
  margin: 1.4rem 0;
  background: color-mix(in srgb, var(--accent) 6%, transparent);
}
.callout.warn { border-left-color: var(--warn); background: color-mix(in srgb, var(--warn) 8%, transparent); }
.callout .label {
  font-family: ui-sans-serif, system-ui, sans-serif;
  font-size: 0.7rem; letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--muted); display: block; margin-bottom: 0.3rem;
}

/* quiz widget (shared component: assets/quiz.js) */
.quiz { margin: 1.6rem 0; }
.quiz .q { font-weight: 600; margin-bottom: 0.6rem; }
.quiz .opt {
  display: block; width: 100%; text-align: left;
  font: inherit; font-size: 0.95rem;
  background: var(--paper); color: var(--ink);
  border: 1px solid var(--rule); border-radius: 6px;
  padding: 0.55rem 0.8rem; margin: 0.35rem 0; cursor: pointer;
  transition: border-color .12s, background .12s;
}
.quiz .opt:hover { border-color: var(--accent); }
.quiz .opt.correct { border-color: var(--ok); background: color-mix(in srgb, var(--ok) 14%, transparent); }
.quiz .opt.wrong { border-color: var(--warn); background: color-mix(in srgb, var(--warn) 14%, transparent); }
.quiz .fb { margin-top: 0.5rem; font-size: 0.9rem; color: var(--muted); min-height: 1.2rem; }

.nav {
  margin-top: 3.5rem; padding-top: 1rem; border-top: 1px solid var(--rule);
  font-family: ui-sans-serif, system-ui, sans-serif; font-size: 0.85rem;
  display: flex; justify-content: space-between; gap: 1rem; flex-wrap: wrap;
}

.ask {
  margin-top: 2.5rem; font-size: 0.9rem; color: var(--muted);
  font-family: ui-sans-serif, system-ui, sans-serif;
}
footer { margin-top: 2rem; color: var(--muted); font-size: 0.8rem; }

/* index page (assets shared): grouped lesson cards */
.idx-group { margin: 2.2rem 0 0; }
.idx-group > h2 { margin-bottom: 0.9rem; }
.idx-group > .sub {
  font-family: ui-sans-serif, system-ui, sans-serif;
  font-size: 0.8rem; color: var(--muted); margin: -0.4rem 0 1rem;
}
.idx-list { list-style: none; margin: 0; padding: 0; }
.idx-list li { margin: 0 0 0.55rem; }
.idx-list a {
  display: flex; align-items: baseline; gap: 0.7rem;
  text-decoration: none; color: var(--ink);
  border: 1px solid var(--rule); border-radius: 7px;
  padding: 0.6rem 0.85rem;
  transition: border-color .12s, background .12s;
}
.idx-list a:hover { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 5%, transparent); }
.idx-num {
  font-family: ui-monospace, monospace; font-size: 0.78rem;
  color: var(--accent); font-weight: 600; min-width: 2.2rem; flex-shrink: 0;
}
.idx-body { display: flex; flex-direction: column; gap: 0.15rem; }
.idx-title { font-size: 0.98rem; font-weight: 600; }
.idx-hook {
  font-family: ui-sans-serif, system-ui, sans-serif;
  font-size: 0.8rem; color: var(--muted); line-height: 1.4;
}