/* Lesson page layout */
.lesson-hero {
  padding: 64px 0 40px;
  border-bottom: 1px solid var(--rule);
  position: relative;
}
.lesson-hero .lesson-num {
  font-family: var(--mono);
  font-size: 0.85rem;
  color: var(--amber-ink);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 14px;
  display: flex; align-items: center; gap: 12px;
}
.lesson-hero .lesson-num::after {
  content: ''; flex: 1; height: 1px; background: var(--rule);
  max-width: 200px;
}
.lesson-hero h1 {
  margin-bottom: 14px;
  font-size: clamp(2.4rem, 5vw, 4rem);
}
.lesson-hero .subtitle {
  font-family: var(--serif);
  font-size: clamp(1.15rem, 1.7vw, 1.4rem);
  color: var(--ink-2);
  font-style: italic;
  max-width: 720px;
  line-height: 1.4;
  font-weight: 400;
}
.lesson-hero .meta {
  display: flex; gap: 18px; margin-top: 22px;
  font-size: 0.86rem; color: var(--ink-3);
}
.lesson-hero .meta span { display: inline-flex; align-items: center; gap: 6px; }

.lesson-body {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 64px;
  padding: 48px 0 120px;
  align-items: start;
}
@media (max-width: 900px) {
  .lesson-body { grid-template-columns: 1fr; gap: 32px; }
  .lesson-sidebar { display: none; }
}
.lesson-sidebar {
  position: sticky; top: 96px;
  align-self: start;
  font-size: 0.85rem;
  color: var(--ink-3);
  max-height: calc(100vh - 120px);
  overflow-y: auto;
  padding-right: 8px;
}
.lesson-sidebar .tiny {
  margin-bottom: 12px;
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-3);
  opacity: 0.7;
}
.lesson-sidebar ol {
  list-style: none; padding: 0; margin: 0;
  border-left: 1px solid var(--rule);
  counter-reset: toc;
}
.lesson-sidebar li {
  counter-increment: toc;
  padding: 7px 0 7px 18px;
  margin-left: -1px;
  border-left: 2px solid transparent;
  cursor: pointer;
  transition: color .18s, border-color .18s, transform .18s;
  color: var(--ink-3);
  font-size: 0.88rem;
  line-height: 1.4;
  position: relative;
}
.lesson-sidebar li::before {
  content: counter(toc, decimal-leading-zero);
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--ink-3);
  opacity: 0.45;
  margin-right: 10px;
  letter-spacing: 0.04em;
}
.lesson-sidebar li:hover { color: var(--ink); transform: translateX(2px); }
.lesson-sidebar li:hover::before { opacity: 0.8; }
.lesson-sidebar li.active {
  color: var(--amber-ink);
  border-left-color: var(--amber-ink);
  font-weight: 500;
}
.lesson-sidebar li.active::before { color: var(--amber-ink); opacity: 1; }

.lesson-content { min-width: 0; }
.lesson-content section {
  padding: 24px 0 32px;
  scroll-margin-top: 80px;
}
.lesson-content section + section { border-top: 1px solid var(--rule); }

.pull-quote {
  font-family: var(--serif);
  font-size: 1.5rem;
  line-height: 1.3;
  color: var(--ink);
  padding: 20px 0 20px 24px;
  border-left: 3px solid var(--amber);
  margin: 28px 0;
  font-weight: 500;
  letter-spacing: -0.01em;
  text-wrap: balance;
}

.callout {
  padding: 16px 18px;
  border-radius: 10px;
  background: var(--amber-wash);
  border: 1px solid oklch(0.86 0.06 75);
  font-size: 0.95rem;
  display: flex;
  gap: 12px;
  margin: 18px 0;
}
.callout .icon { flex-shrink: 0; font-family: var(--serif); font-weight: 700; font-size: 1.1rem; color: var(--amber-ink); }
.callout b { color: var(--ink); }
.callout.ink { background: var(--ink); color: var(--paper-2); border: none; }
.callout.ink .icon { color: var(--amber); }
.callout.ink b { color: var(--paper); }

/* two-col layout helpers */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
@media (max-width: 780px) { .grid-2, .grid-3 { grid-template-columns: 1fr; } }

.do-dont {
  display: grid; grid-template-columns: 1fr 1fr; gap: 18px; margin: 22px 0;
}
.do-dont > div {
  padding: 16px 18px;
  border-radius: 10px;
  font-size: 0.92rem;
}
.do-dont .do {
  background: color-mix(in oklch, var(--ok) 10%, var(--paper));
  border: 1px solid color-mix(in oklch, var(--ok) 40%, var(--rule));
}
.do-dont .dont {
  background: color-mix(in oklch, var(--bad) 8%, var(--paper));
  border: 1px solid color-mix(in oklch, var(--bad) 30%, var(--rule));
}
.do-dont .label {
  font-family: var(--mono); text-transform: uppercase; font-size: 0.7rem; letter-spacing: 0.08em;
  display: inline-block; padding: 2px 8px; border-radius: 4px; margin-bottom: 8px;
}
.do-dont .do .label { background: var(--ok-ink); color: var(--paper); }
.do-dont .dont .label { background: var(--bad-ink); color: var(--paper); }
@media (max-width: 640px) { .do-dont { grid-template-columns: 1fr; } }

.lesson-footer {
  display: flex; justify-content: space-between; align-items: center;
  padding: 28px; margin-top: 36px;
  background: var(--ink);
  color: var(--paper);
  border-radius: var(--radius-lg);
  gap: 20px;
  flex-wrap: wrap;
}
.lesson-footer h3 { color: var(--paper); font-size: 1.3rem; }
.lesson-footer .small { color: oklch(0.85 0.02 70); }

.nav-prev-next {
  display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 24px;
}
.nav-prev-next a {
  display: block; padding: 16px 18px;
  background: var(--paper-2); border: 1px solid var(--rule);
  border-radius: var(--radius); text-decoration: none;
  transition: border-color .15s, background .15s;
}
.nav-prev-next a:hover { border-color: var(--amber-ink); background: var(--paper); text-decoration: none; }
.nav-prev-next .tiny { color: var(--ink-3); }
.nav-prev-next .title { font-family: var(--serif); font-weight: 600; color: var(--ink); margin-top: 4px; font-size: 1.05rem; }
.nav-prev-next .next { text-align: right; }
@media (max-width: 640px) { .nav-prev-next { grid-template-columns: 1fr; } }

/* ===== Narrow-viewport widget overflow guards (<=480px) =====
   The interactive widgets use inline grid/flex layouts with fixed track sizes
   and nowrap buttons. On phones (down to 320px) these push past the viewport.
   These rules only apply at <=480px, so desktop (>=720px) layout is untouched. */
@media (max-width: 480px) {
  /* Flex rows of [input flex:1] + [nowrap button]: a flex item's default
     min-width:auto keeps the input from shrinking, so the button overflows.
     Let the input collapse, and allow the row to wrap if still too tight. */
  .card input,
  .card textarea,
  .card select { min-width: 0; }
  .card .btn { max-width: 100%; }
  /* Fixed two-column widget grids (1fr 1fr, 1.1fr 1fr, 140px 1fr, 1fr auto)
     can't shrink below their content on a phone, so the right-hand panel
     (usually a <pre>) is pushed past the edge. Collapse just these to a single
     column; auto-fit/minmax grids already reflow and are left alone. */
  .card div[style*="1fr 1fr"],
  .card div[style*="1.1fr 1fr"],
  .card div[style*="140px 1fr"],
  .card div[style*="1fr auto"] {
    grid-template-columns: 1fr !important;
    min-width: 0;
  }
  .card [style*="grid-template-columns"] > * { min-width: 0; }
  /* Code/pre inside widgets: keep wrapping, never force a min-content width. */
  .card pre.code,
  .card pre { max-width: 100%; min-width: 0; overflow-x: auto; overflow-wrap: anywhere; word-break: break-word; }
  /* Long unbreakable tokens (ids, keys, paths) in drills must wrap. */
  .card span, .card code, .card .mono { overflow-wrap: anywhere; }
}