:root {
  color-scheme: dark;
  --background: #0b111a;
  --surface: #101c2a;
  --border: #29394a;
  --text: #e8eff4;
  --muted: #a4b5c9;
  --accent: #62d6c3;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--background); color: var(--text); font: 16px/1.6 system-ui, sans-serif; }
a { color: var(--accent); text-underline-offset: 4px; }
a:hover { color: var(--text); }
button, summary { font: inherit; }
button { color: inherit; }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 4px; }
.skip { position: absolute; top: 8px; left: 16px; padding: 8px 16px; background: var(--surface); z-index: 2; transform: translateY(-150%); }
.skip:focus { transform: none; }
.masthead, main, .site-footer { max-width: 1440px; margin: auto; padding-inline: 40px; }
.masthead { display: flex; justify-content: space-between; align-items: center; min-height: 88px; gap: 24px; border-bottom: 1px solid var(--border); }
.brand { color: var(--accent); font-size: 14px; font-weight: 750; letter-spacing: .07em; text-decoration: none; }
.brand span { color: var(--muted); font-weight: 500; }
.hardware { font-size: 12px; color: var(--muted); }
.intro { padding-block: 40px 32px; }
.eyebrow { color: var(--accent); margin: 0 0 8px; font-size: 12px; letter-spacing: .09em; text-transform: uppercase; }
h1 { font-size: clamp(32px, 4vw, 52px); line-height: 1.1; letter-spacing: -.035em; margin: 0 0 16px; }
.lede { color: var(--muted); margin: 0; max-width: 700px; font-size: 17px; }
.walkthrough { display: grid; grid-template-columns: minmax(0, 1fr) 300px; gap: 24px; align-items: start; scroll-margin-top: 16px; }
.player { min-width: 0; overflow: hidden; border: 1px solid var(--border); border-radius: 8px; background: var(--surface); }
video { display: block; width: 100%; height: auto; aspect-ratio: 16/9; background: #080d14; }
.player-footer { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 12px; padding: 16px 20px; }
.player-footer p { color: var(--muted); font-size: 12px; margin: 0; }
.player-footer p span { padding-inline: 4px; }
.player-footer a { font-size: 13px; white-space: nowrap; }
.status { color: var(--muted); padding: 0 20px 16px; margin: 0; }
.chapter-heading { padding: 0 12px 12px; }
h2 { font-size: 17px; margin: 0 0 4px; line-height: 1.5; }
.chapter-heading p { color: var(--muted); font-size: 12px; margin: 0; }
.chapters ol { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--border); }
.chapters li { border-bottom: 1px solid var(--border); }
.chapters button { width: 100%; display: flex; text-align: left; align-items: baseline; gap: 16px; padding: 12px; background: transparent; border: 0; border-left: 2px solid transparent; cursor: pointer; min-height: 68px; }
.chapters button:hover { background: var(--surface); }
.chapters button[aria-current="true"] { border-left-color: var(--accent); background: #142e33; }
.chapter-time { font: 12px/1.6 ui-monospace, monospace; color: var(--accent); flex-shrink: 0; }
.chapters strong { display: block; font-size: 13px; font-weight: 600; }
.chapters small { display: block; color: var(--muted); font-size: 12px; margin-top: 2px; }
.notes { padding-block: 32px; border-bottom: 1px solid var(--border); }
.note-columns { display: grid; grid-template-columns: 1fr 1fr; gap: 32px; }
.notes p { color: var(--muted); font-size: 14px; margin: 12px 0 0; }
.notes strong { color: var(--text); }
.transcript { border-bottom: 1px solid var(--border); padding-block: 20px; }
summary { width: fit-content; color: var(--accent); cursor: pointer; font-size: 14px; }
.transcript p { color: var(--muted); font-size: 14px; max-width: 900px; }
.transcript time { display: block; color: var(--accent); font: 12px/1.6 ui-monospace, monospace; margin-bottom: 4px; }
.site-footer { display: flex; justify-content: space-between; gap: 16px; padding-block: 24px; color: var(--muted); font-size: 12px; }
.no-script { color: var(--muted); font-size: 12px; }
@media (max-width: 980px) {
  .walkthrough { grid-template-columns: 1fr; }
  .chapters ol { display: grid; grid-template-columns: 1fr 1fr; }
  .chapters li { min-width: 0; }
  .chapter-heading { padding-left: 0; }
}
@media (max-width: 600px) {
  .masthead, main, .site-footer { padding-inline: 20px; }
  .masthead { flex-direction: column; align-items: flex-start; justify-content: center; gap: 4px; min-height: 80px; }
  .intro { padding-block: 28px 24px; }
  .lede { font-size: 15px; }
  .wide { display: none; }
  .player-footer { padding: 12px; }
  .chapters ol, .note-columns { grid-template-columns: 1fr; }
  .note-columns { gap: 8px; }
  .site-footer { flex-direction: column; gap: 4px; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }