/* Learn / criteria page */
.learn-hero {
  border-radius: var(--r-lg); padding: 38px 40px;
  background: var(--surface);
  border: 1px solid var(--border); box-shadow: var(--shadow-card);
  position: relative; overflow: hidden;
}
.learn-hero::before { content: ""; position: absolute; left: 0; top: 0; bottom: 0; width: 3px; background: var(--blue); }
.learn-kicker { font-family: var(--font-mono); font-size: 11px; letter-spacing: .16em; text-transform: uppercase; color: var(--cyan-soft); }
.learn-hero h1 { font-family: var(--font-display); font-weight: 600; font-size: clamp(26px, 3.2vw, 38px); letter-spacing: -0.03em; line-height: 1.12; margin: 10px 0 12px; max-width: 760px; }
.learn-hero p { color: var(--text-dim); font-size: 15px; line-height: 1.65; max-width: 680px; margin: 0 0 22px; }

.learn-block { margin-top: 38px; }
.learn-block > h2 { font-family: var(--font-display); font-weight: 600; font-size: 22px; letter-spacing: -0.02em; margin: 0 0 6px; }
.learn-sub { color: var(--text-dim); font-size: 14px; line-height: 1.6; margin: 0 0 18px; max-width: 720px; }

.pillar-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-top: 16px; }
.pillar { padding: 22px; }
.pillar-ic { font-size: 26px; line-height: 1; margin-bottom: 12px; }
.pillar h3 { font-family: var(--font-display); font-weight: 600; font-size: 16px; margin: 0 0 8px; letter-spacing: -0.01em; }
.pillar p { color: var(--text-dim); font-size: 13.5px; line-height: 1.6; margin: 0; }

.crit-list { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.crit { padding: 20px 22px; }
.crit-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 8px; }
.crit-name { font-family: var(--font-display); font-weight: 600; font-size: 15.5px; letter-spacing: -0.01em; }
.crit-band { flex: none; font-family: var(--font-mono); font-size: 11px; font-weight: 600; padding: 4px 10px; border-radius: var(--r-pill);
  background: rgba(52,211,153,0.14); color: #6EE7B7; border: 1px solid rgba(52,211,153,0.3); white-space: nowrap; }
.crit p { color: var(--text-dim); font-size: 13.5px; line-height: 1.6; margin: 0 0 12px; }
.crit-src { font-family: var(--font-mono); font-size: 10.5px; letter-spacing: .03em; color: var(--text-faint); padding-top: 10px; border-top: 1px dashed var(--border); }

.score-formula { display: flex; align-items: center; flex-wrap: wrap; gap: 14px; padding: 22px 24px; margin-top: 8px; }
.sf-item { display: flex; flex-direction: column; gap: 4px; min-width: 90px; }
.sf-w { font-family: var(--font-display); font-weight: 700; font-size: 28px; letter-spacing: -0.02em;
  color: var(--blue-bright); line-height: 1; }
.sf-item > span:last-child { font-size: 13px; color: var(--text-dim); }
.sf-plus { font-family: var(--font-display); font-size: 22px; color: var(--text-faint); }
.learn-note, .learn-disclaimer { color: var(--text-dim); font-size: 13.5px; line-height: 1.65; margin: 16px 0 0; max-width: 760px; }
.learn-disclaimer { color: var(--text-faint); font-size: 12.5px; }

.tip-list, .src-list { margin: 8px 0 0; padding: 0; list-style: none; display: flex; flex-direction: column; gap: 10px; }
.tip-list li, .src-list li { position: relative; padding: 12px 14px 12px 38px; border-radius: var(--r-md);
  background: var(--surface); border: 1px solid var(--border); font-size: 13.5px; line-height: 1.6; color: var(--text-dim); }
.tip-list li b { color: var(--text); font-weight: 600; }
.tip-list li::before { content: "✓"; position: absolute; left: 14px; top: 12px; color: #6EE7B7; font-weight: 700; }
.src-list li { padding-left: 14px; font-family: var(--font-mono); font-size: 12px; color: var(--text-faint); }

/* APA 7th-edition reference list — numbered, hanging-indent feel, clickable links. */
.src-list--apa { list-style: none; counter-reset: src; }
.src-list--apa li {
  counter-increment: src;
  font-family: var(--font-body);
  font-size: 13px;
  line-height: 1.7;
  color: var(--text-dim);
  padding: 12px 16px 12px 42px;
}
.src-list--apa li::before {
  content: counter(src) ".";
  position: absolute; left: 14px; top: 12px;
  font-family: var(--font-mono); font-weight: 700; font-size: 12px;
  color: var(--blue-bright);
}
.src-list--apa li i { font-style: italic; color: var(--text); }
.src-list--apa li a { color: var(--blue-bright); text-decoration: underline; text-underline-offset: 2px; word-break: break-word; }
.src-list--apa li a:hover { color: var(--text); }

/* Practice-video cards */
.vid-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 14px; margin-top: 16px; }
.vid-card { display: flex; flex-direction: column; border-radius: var(--r-md); overflow: hidden;
  background: var(--surface); border: 1px solid var(--border); }
.vid-thumb { position: relative; display: block; aspect-ratio: 16/9; background: var(--surface-2); overflow: hidden; }
/* Skeleton shimmer over the placeholder until the thumbnail image has loaded. */
.vid-thumb::before {
  content: ''; position: absolute; inset: 0; z-index: 1; transform: translateX(-100%);
  background: linear-gradient(90deg, transparent, rgba(120,150,210,0.12), transparent);
  animation: pp-shimmer 1.4s infinite;
}
.vid-thumb.loaded::before { display: none; animation: none; }
/* Image sits above the shimmer (z-index 2); once its opaque pixels load they cover the
   shimmer even if JS never runs, so a failed learn.js can't leave a blank thumbnail. */
.vid-thumb img { width: 100%; height: 100%; object-fit: cover; display: block; position: relative; z-index: 2; transition: transform var(--dur) var(--ease); }
.vid-play { z-index: 3; }
@media (prefers-reduced-motion: reduce) { .vid-thumb::before { animation: none; } }
.vid-card:hover .vid-thumb img { transform: scale(1.05); }
.vid-play { position: absolute; inset: 0; margin: auto; width: 44px; height: 44px; border-radius: 50%;
  background: rgba(8,11,18,0.72); border: 1px solid rgba(255,255,255,0.25); }
.vid-play::after { content: ""; position: absolute; left: 50%; top: 50%; transform: translate(-40%,-50%);
  border-style: solid; border-width: 8px 0 8px 13px; border-color: transparent transparent transparent #fff; }
.vid-meta { display: flex; flex-direction: column; gap: 4px; padding: 12px 14px; }
.vid-tag { font-family: var(--font-mono); font-size: 10px; letter-spacing: .04em; color: var(--blue-bright); }
.vid-title { font-family: var(--font-display); font-weight: 600; font-size: 14px; line-height: 1.35; color: var(--text); }
.vid-by { font-size: 12px; color: var(--text-faint); margin-top: 2px; }

@media (max-width: 900px) {
  .pillar-grid { grid-template-columns: 1fr; }
  .crit-list { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  .learn-hero { padding: 26px 18px; }
  .learn-block > h2 { font-size: 19px; }
}