:root {
  --iq-blue-light: #6bbfff;
  --iq-blue: #3a8fe8;
  --iq-bg: #080f1c;
  --iq-surface: #0e1929;
  --iq-surface2: #152237;
  --iq-border: rgba(58, 143, 232, 0.25);
  --iq-text: #e8f0fc;
  --iq-muted: #93a8c9;
  --font-display: 'DM Serif Display', serif;
  --font-body: 'DM Sans', sans-serif;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  background: radial-gradient(circle at 15% 0, rgba(107, 191, 255, 0.15), transparent 40%), var(--iq-bg);
  color: var(--iq-text);
  font-family: var(--font-body);
  line-height: 1.65;
}
a { color: var(--iq-blue-light); }
a:focus-visible, button:focus-visible { outline: 2px solid var(--iq-blue-light); outline-offset: 4px; }
.page { max-width: 1100px; margin: auto; padding: 24px; }
.back-link { display: inline-block; margin-bottom: 20px; text-decoration: none; font-size: 14px; }
.panel { background: var(--iq-surface); border: 1px solid var(--iq-border); border-radius: 16px; padding: 24px; margin-bottom: 24px; }
.hero { display: grid; grid-template-columns: 1fr 1.2fr; align-items: center; gap: 24px; }
.cover { width: 100%; aspect-ratio: 4 / 3; object-fit: cover; border-radius: 12px; }
.cover-natural { height: auto; aspect-ratio: auto; display: block; }
h1, h2 { font-family: var(--font-display); line-height: 1.2; margin: 0 0 16px; }
h1 { font-size: clamp(30px, 5vw, 44px); }
h2 { font-size: 28px; }
h3 { font-size: 18px; line-height: 1.4; margin: 8px 0; }
p { color: var(--iq-muted); margin: 0 0 16px; }
ul { padding-left: 20px; color: var(--iq-muted); }
.meta, .actions { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 16px; }
.pill { font-size: 12px; color: var(--iq-blue-light); border: 1px solid var(--iq-border); border-radius: 999px; padding: 4px 10px; }
.free { color: #4ade80; background: rgba(74, 222, 128, 0.1); border-color: rgba(74, 222, 128, 0.3); }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 10px 16px;
  background: var(--iq-blue);
  color: #fff;
  border: 1px solid transparent;
  border-radius: 9px;
  font: inherit;
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
}
.btn:hover { background: #2670cc; }
.outline { background: var(--iq-surface2); border-color: var(--iq-border); }
.overview { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
.overview > div, .hero > div, .lesson { min-width: 0; }
.overview p:last-child { margin-bottom: 0; }
.player-section { scroll-margin-top: 20px; }
.player-section:focus { outline: none; }
.video-wrap { position: relative; aspect-ratio: 16 / 9; background: #000; border: 1px solid var(--iq-border); border-radius: 12px; overflow: hidden; margin-bottom: 16px; }
.video-wrap iframe { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; }
.video-placeholder { display: grid; place-content: center; text-align: center; height: 100%; padding: 20px; }
.video-placeholder p { margin: 0; }
.playback-note, .source-note { font-size: 13px; }
.lessons { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; }
.lesson { display: flex; flex-direction: column; border: 1px solid var(--iq-border); border-radius: 12px; overflow: hidden; background: var(--iq-surface2); }
.lesson.is-selected { border-color: var(--iq-blue-light); }
.lesson img { display: block; width: 100%; aspect-ratio: 16 / 9; object-fit: cover; }
.lesson-body { padding: 20px; display: flex; flex-direction: column; flex: 1; }
.lesson-number { color: var(--iq-blue-light); font-size: 12px; text-transform: uppercase; }
.lesson-published { font-size: 13px; }
.lesson-credits { margin: 0 0 20px; font-size: 13px; overflow-wrap: anywhere; }
.lesson-credits dt { color: var(--iq-blue-light); font-weight: 600; }
.lesson-credits dd { margin: 0 0 10px; color: var(--iq-muted); }
.lesson .actions { margin-top: auto; margin-bottom: 0; align-items: center; }
.lesson .actions a { font-size: 13px; }
footer { display: flex; flex-wrap: wrap; justify-content: center; gap: 20px; padding: 24px; font-size: 13px; border-top: 1px solid var(--iq-border); }
[hidden] { display: none !important; }
@media (max-width: 768px) {
  .page { padding: 20px; }
  .panel { padding: 20px; }
  .hero, .overview, .lessons { grid-template-columns: 1fr; }
}