/* ── Learn (templates/learn/) ─────────────────────────────────
   A lecture hall's manners: the course is a list to work through, the
   lecture fills the stage. Card frames have a fixed shape, so nothing
   moves as pictures arrive; a course without a picture shows its source
   and number instead. Colours are the site's tokens; the stage is dark in
   both themes, as a hall with the lights down. */

/* ── Hero and search ─────────────────────────────────────── */
.learn-hero {
  padding: clamp(1.5rem, 4vw, 3.25rem) var(--gutter) clamp(1.25rem, 3vw, 2rem);
  background: var(--hero-band);
}
.learn-hero-title { margin: 0 0 0.75rem; }
.learn-lede { font-size: var(--step-1); line-height: 1.5; color: var(--text-muted); max-width: 42rem; margin: 0 0 1.25rem; }
.learn-actions { display: flex; flex-wrap: wrap; gap: 0.6rem; margin: 0; }
.learn-empty { padding: 2rem var(--gutter); }

/* ── Cards and rails ──────────────────────────────────────── */
.learn-rail { padding-top: 1.25rem; }
.learn-rail-head { display: flex; align-items: baseline; justify-content: space-between; gap: 1rem; padding: 0 var(--gutter); }
.learn-rail-head .section-title a { color: inherit; text-decoration: none; }
.learn-rail-head .section-title a:hover { text-decoration: underline; }
.learn-more { color: var(--accent-text); font-size: var(--step--1); white-space: nowrap; }
.learn-rail-track { align-items: flex-start; }

.learn-card {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  min-width: 0;
  color: var(--text);
  text-decoration: none;
  border-radius: var(--radius);
}
.learn-rail-track .learn-card { flex: 0 0 auto; width: clamp(200px, 24vw, 280px); }
.learn-card-frame {
  position: relative;
  display: block;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: var(--placeholder);
  border-radius: var(--radius);
  box-shadow: 0 0 0 1px var(--hairline) inset;
  transition: transform var(--duration-normal) var(--spring-smooth), box-shadow var(--duration-normal) ease;
}
.learn-card-frame img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; }
.learn-card-mark {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  padding: 0.75rem 0.85rem;
  gap: 0.15rem;
}
.learn-card-source { font-size: var(--step--2); font-weight: 700; text-transform: uppercase; letter-spacing: 0.08em; color: var(--text-muted); }
.learn-card-number { font-family: var(--font-serif); font-size: var(--step-2); font-weight: 600; line-height: 1.1; color: var(--text); overflow-wrap: anywhere; }
.learn-card-badge {
  position: absolute;
  top: 0.5rem;
  left: 0.5rem;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: var(--step--2);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  background: var(--glass);
  color: var(--on-media);
  border: 1px solid var(--glass-border);
}
.learn-card:hover .learn-card-frame,
.learn-card:focus-visible .learn-card-frame { transform: translateY(-3px); box-shadow: var(--shadow-2); }
.learn-card:focus-visible { outline: none; }
:root .learn-card.controller-focus,
:root[data-tv] .learn-card.controller-focus { outline: none !important; box-shadow: none !important; }
.learn-card:focus-visible .learn-card-frame,
.learn-card.controller-focus .learn-card-frame { outline: 3px solid var(--focus-ring); outline-offset: 3px; }
.learn-card-title {
  margin-top: 0.45rem;
  font-weight: 600;
  font-size: var(--step--1);
  line-height: 1.3;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.learn-card-meta,
.learn-card-size { font-size: var(--step--2); color: var(--text-muted); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
/* "Continue learning": words alone, on a tile. */
.learn-card--continue {
  padding: 0.75rem 0.9rem;
  background: var(--surface);
  box-shadow: 0 0 0 1px var(--hairline) inset;
  min-height: 5.5rem;
  justify-content: flex-end;
}
.learn-card--continue .learn-card-title { margin-top: 0; }

.learn-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 230px), 1fr));
  gap: 1.5rem 1.1rem;
  padding: 0.5rem var(--gutter) 2.5rem;
}

.learn-ways { padding-top: 1.25rem; }
.learn-chips { list-style: none; display: flex; flex-wrap: wrap; gap: 0.5rem; margin: 0; padding: 0 var(--gutter); }
.learn-chips .count { color: var(--text-dim); font-variant-numeric: tabular-nums; margin-left: 0.25em; }

.learn-about { padding: 2rem var(--gutter) 3rem; max-width: 72rem; }
.learn-about > p { max-width: 70ch; line-height: 1.65; color: var(--text-muted); }
.learn-credits { line-height: 1.8; color: var(--text-muted); padding-left: 1.25rem; }
.learn-credits a, .learn-about a { color: var(--accent-text); text-decoration: underline; text-underline-offset: 0.15em; }
.learn-policy { margin-top: 1rem; max-width: 70ch; }
.learn-policy summary { cursor: pointer; font-weight: 600; }
.learn-policy table { border-collapse: collapse; margin-top: 0.75rem; font-size: var(--step--1); }
.learn-policy th, .learn-policy td { text-align: left; vertical-align: top; padding: 0.4rem 0.75rem 0.4rem 0; border-top: 1px solid var(--hairline); }
.learn-policy th { white-space: nowrap; }

/* ── Browse ───────────────────────────────────────────────── */
.learn-browse-head { padding: 1.5rem var(--gutter) 0.5rem; }
.learn-crumbs { font-size: var(--step--1); color: var(--text-muted); margin: 0 0 0.4rem; }
.learn-crumbs a { color: var(--accent-text); }
.learn-filters { display: flex; flex-wrap: wrap; gap: 0.6rem 0.9rem; align-items: flex-end; margin: 0.75rem 0; }
.learn-filters label { display: flex; flex-direction: column; gap: 0.25rem; font-size: var(--step--2); color: var(--text-muted); min-width: 0; max-width: 100%; }
.learn-filters select { font: inherit; font-size: var(--step--1); padding: 0.4rem 0.5rem; border-radius: var(--radius); border: 1px solid var(--border-strong); background: var(--surface); color: var(--text); max-width: 100%; }
.learn-filters .learn-check { flex-direction: row; align-items: center; gap: 0.4rem; font-size: var(--step--1); color: var(--text); padding-bottom: 0.45rem; }
.learn-applied { list-style: none; display: flex; flex-wrap: wrap; gap: 0.5rem; align-items: center; padding: 0; margin: 0.5rem 0 0; }
.learn-applied a:not(.filter-pill) { color: var(--accent-text); font-size: var(--step--1); text-decoration: underline; }
.learn-pages { display: flex; flex-wrap: wrap; gap: 0.4rem; justify-content: center; padding: 0 var(--gutter) 3rem; }

/* ── A course ─────────────────────────────────────────────── */
.learn-course { padding-bottom: 3rem; }
.learn-course-head { padding: 1.5rem var(--gutter) 1.25rem; background: var(--hero-band); }
.learn-course-top { display: grid; grid-template-columns: minmax(0, 360px) minmax(0, 1fr); gap: clamp(1rem, 3vw, 2rem); align-items: start; max-width: 72rem; }
.learn-course-top:not(:has(.learn-course-picture)) { grid-template-columns: minmax(0, 1fr); }
.learn-course-picture { aspect-ratio: 16 / 9; border-radius: var(--radius-lg); overflow: hidden; background: var(--placeholder); box-shadow: 0 0 0 1px var(--hairline) inset; }
.learn-course-picture img { width: 100%; height: 100%; object-fit: cover; display: block; }
.learn-course-kind { display: flex; flex-wrap: wrap; gap: 0.35rem 0.75rem; align-items: center; font-size: var(--step--1); color: var(--text-muted); margin: 0 0 0.5rem; font-variant-numeric: tabular-nums; }
.learn-badge { padding: 2px 8px; border-radius: 4px; font-size: var(--step--2); font-weight: 700; text-transform: uppercase; letter-spacing: 0.06em; background: var(--tint-strong); color: var(--text); }
.learn-course-title, .learn-lecture-title { font-size: var(--step-4); font-weight: 800; letter-spacing: -0.03em; line-height: 1.08; margin: 0 0 0.5rem; overflow-wrap: anywhere; }
.learn-lecture-title { font-size: var(--step-3); }
.learn-course-by { color: var(--text-muted); margin: 0 0 1rem; }
.learn-course-actions { display: flex; flex-wrap: wrap; gap: 0.6rem; margin: 0; }
.learn-course-about, .learn-course-lectures, .learn-course-materials, .learn-course-facts { padding: 1.5rem var(--gutter) 0; max-width: 72rem; }
.learn-course-about > p { max-width: 70ch; line-height: 1.65; color: var(--text-muted); overflow-wrap: anywhere; }
.learn-note { color: var(--text-muted); font-size: var(--step--1); margin: 0 0 0.5rem; }
.learn-links { display: flex; flex-wrap: wrap; gap: 0.5rem 1.25rem; padding-left: 1.1rem; margin: 0; }
.learn-links a, .learn-facts a { color: var(--accent-text); text-decoration: underline; text-underline-offset: 0.15em; }
.learn-group { font-size: var(--step-0); font-weight: 700; margin: 1.25rem 0 0.4rem; color: var(--text); }
.learn-lectures { margin: 0; padding-left: 2.2rem; display: grid; gap: 0.15rem; max-width: 60rem; }
.learn-lectures li { padding: 0.15rem 0; }
.learn-lectures li::marker { color: var(--text-dim); font-variant-numeric: tabular-nums; }
.learn-lecture { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 0.15rem 1rem; padding: 0.45rem 0.6rem; border-radius: var(--radius); color: var(--text); text-decoration: none; }
.learn-lecture:hover, .learn-lecture:focus-visible { background: var(--tint-strong); }
.learn-lecture-title { font-weight: 500; }
.learn-lecture .learn-lecture-title { font-size: var(--step-0); letter-spacing: 0; line-height: 1.4; margin: 0; font-weight: 500; }
.learn-lecture-meta { font-size: var(--step--1); color: var(--text-muted); font-variant-numeric: tabular-nums; }
.learn-lecture--current .learn-lecture { background: var(--tint-strong); box-shadow: inset 3px 0 0 var(--accent); }
.learn-facts { display: grid; grid-template-columns: max-content minmax(0, 1fr); gap: 0.5rem 1.25rem; font-size: var(--step--1); margin: 0; }
.learn-facts dt { color: var(--text-dim); font-weight: 600; }
.learn-facts dd { margin: 0; color: var(--text-muted); overflow-wrap: anywhere; }

/* ── A lecture ────────────────────────────────────────────── */
.learn-lecture-page { padding-bottom: 3rem; }
.learn-stage { background: var(--media-bg); padding: 0 var(--gutter); }
.learn-viewport {
  position: relative;
  max-width: 1100px;
  margin: 0 auto;
  aspect-ratio: 16 / 9;
  max-height: 75vh;
  display: grid;
  place-items: center;
  overflow: hidden;
  color: var(--on-media);
  background: var(--media-bg);
}
.learn-viewport--audio { aspect-ratio: 16 / 7; }
.learn-stage-poster { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; opacity: 0.45; }
.learn-play {
  position: relative;
  padding: 0.85rem 2rem;
  border-radius: var(--radius);
  background: var(--action);
  color: var(--on-action);
  font: inherit;
  font-weight: 700;
  border: none;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.5em;
}
.learn-play .icon { width: 1.1em; height: 1.1em; fill: currentColor; }
.learn-play:hover { background: var(--action-hover); }
.learn-embed-note { position: absolute; bottom: 0.75rem; left: 1rem; right: 1rem; margin: 0; text-align: center; font-size: var(--step--2); color: var(--on-media-muted); }
.learn-embed-note a { color: var(--on-media); text-decoration: underline; }
.learn-embed-frame { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; }
.learn-away { gap: 1rem; text-align: center; align-content: center; }
.learn-away p { margin: 0; color: var(--on-media-muted); }
.learn-lecture-head { padding: 1.25rem var(--gutter) 0; max-width: 72rem; }
.learn-prevnext { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 0.75rem; padding: 1.25rem var(--gutter) 0; max-width: 72rem; }
.learn-prevnext a { flex: 1 1 16rem; max-width: 30rem; padding: 0.75rem 1rem; border-radius: var(--radius); border: 1px solid var(--hairline); color: var(--text); text-decoration: none; background: var(--surface); }
.learn-prevnext a:hover, .learn-prevnext a:focus-visible { background: var(--tint-strong); }
.learn-next { text-align: right; margin-left: auto; }
.learn-prevnext-dir { display: block; font-size: var(--step--2); font-weight: 700; text-transform: uppercase; letter-spacing: 0.06em; color: var(--text-muted); }
.learn-next--up { border-color: var(--accent); box-shadow: 0 0 0 2px var(--accent); }

@media (max-width: 640px) {
  .learn-course-top { grid-template-columns: minmax(0, 1fr); }
  .learn-course-picture { max-width: 420px; }
  .learn-facts { grid-template-columns: minmax(0, 1fr); gap: 0.15rem; }
  .learn-facts dd { margin-bottom: 0.6rem; }
  .learn-lectures { padding-left: 1.6rem; }
  .learn-viewport--audio { aspect-ratio: 4 / 3; }
}
.learn-lecture--locked { color: var(--text-muted); cursor: default; }
.learn-lecture--locked:hover { background: none; }