:root {
  color-scheme: light;
  --ink: #15211d;
  --muted: #5e6c65;
  --forest: #173a31;
  --moss: #28604d;
  --mint: #dcefe5;
  --cream: #f8f7f1;
  --line: #c9d4ce;
  --focus: #cf7c2e;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }
body { margin: 0; color: var(--ink); background: var(--cream); line-height: 1.55; }
button, input { font: inherit; }
button { cursor: pointer; }
button:disabled { cursor: not-allowed; opacity: .58; }
button:focus-visible, input:focus-visible, a:focus-visible { outline: 3px solid var(--focus); outline-offset: 3px; }
.skip-link { position: absolute; left: -9999px; top: 0; background: white; padding: .6rem; }
.skip-link:focus { left: .75rem; z-index: 10; }
.site-header { padding: 2.75rem 1.15rem 2rem; background: var(--forest); color: #f9fbf7; }
.site-header > *, .layout, footer { max-width: 760px; margin-left: auto; margin-right: auto; }
.eyebrow, .section-label { margin: 0; font-size: .76rem; font-weight: 800; letter-spacing: .11em; text-transform: uppercase; }
.eyebrow { color: #b9ddc9; }
.site-header h1 { max-width: 620px; margin: .35rem auto .65rem; font-size: clamp(2rem, 7vw, 3.3rem); line-height: 1.03; letter-spacing: -.04em; }
.header-copy { color: #d6e6de; max-width: 600px; margin-bottom: 0; }
.layout { padding: 1.5rem 1rem 3rem; }
.lesson-switcher { margin-bottom: 1rem; }
.lesson-tabs, .speed-options, .mode-nav { display: flex; gap: .5rem; flex-wrap: wrap; }
.lesson-tabs { margin-top: .5rem; }
.lesson-tab, .mode-button { padding: .62rem .85rem; background: transparent; color: var(--forest); border: 1px solid var(--line); border-radius: .55rem; font-weight: 700; }
.lesson-tab.active, .mode-button.active { background: var(--mint); border-color: var(--moss); }
.pwa-tools { display: grid; gap: .8rem; margin: 0 0 1rem; padding: 1rem; border: 1px solid #b7d3c3; border-radius: 1rem; background: #f0f7f2; }
.pwa-tools h2 { margin: .12rem 0; color: var(--forest); font-size: 1.3rem; }
.pwa-tools p { margin: .25rem 0; }
.pwa-actions { display: flex; flex-wrap: wrap; gap: .55rem; align-items: center; }
.primary-button { min-height: 2.7rem; padding: .58rem .8rem; border: 0; border-radius: .6rem; color: white; background: var(--forest); font-weight: 800; }
.offline-status { color: var(--muted); font-size: .88rem; }
.pwa-hint { color: var(--muted); font-size: .82rem; }
.road-card { border: 1px solid #b7d3c3; border-radius: 1rem; background: #eef7f1; padding: 1.2rem; box-shadow: 0 7px 20px rgba(22, 55, 45, .06); }
.road-card h2 { margin: .15rem 0; font-size: 1.65rem; }
.road-card p { margin: .25rem 0; }
.road-card-heading { margin-bottom: 1.1rem; }
.transport { display: grid; grid-template-columns: 1fr 1.2fr 1fr; gap: .5rem; align-items: stretch; margin: .9rem 0; }
.transport button { min-height: 3.35rem; border-radius: .75rem; font-weight: 800; }
.rewind { color: var(--forest); background: white; border: 1px solid var(--moss); font-size: 1.02rem; }
.rewind span { font-size: 1.25rem; }
.play-toggle { border: 0; color: white; background: var(--forest); font-size: 1.02rem; }
.quiet-button { color: var(--forest); background: transparent; border: 1px solid var(--line); font-size: .88rem; }
.timeline-row { display: grid; grid-template-columns: 3.3rem 1fr 3.7rem; gap: .5rem; align-items: center; color: var(--muted); font-variant-numeric: tabular-nums; font-size: .82rem; }
.timeline-row input { width: 100%; accent-color: var(--moss); }
.speed-picker { margin: 1rem 0 .7rem; border: 1px solid var(--line); border-radius: .75rem; padding: .75rem; background: rgba(255,255,255,.55); }
.speed-picker legend { color: var(--forest); font-weight: 800; padding: 0 .25rem; }
.speed-picker p { color: var(--muted); font-size: .86rem; margin: .1rem 0 .6rem; }
.speed-option { min-width: 3.75rem; padding: .5rem; border: 1px solid var(--line); border-radius: .45rem; color: var(--forest); background: white; font-weight: 750; }
.speed-option.active { color: white; background: var(--moss); border-color: var(--moss); }
.text-button { margin-top: .6rem; padding: 0; border: 0; color: var(--forest); background: transparent; text-decoration: underline; font-weight: 700; }
.road-note { color: var(--muted); font-size: .78rem; }
.mode-nav { margin: 1.5rem 0 0; }
.lesson-panel { min-height: 350px; padding: 1.4rem 0 0; }
.lesson-panel h1 { margin: 0 0 .55rem; font-size: clamp(1.8rem, 6vw, 2.7rem); line-height: 1.1; letter-spacing: -.03em; }
.lesson-panel h2 { margin-top: 2rem; color: var(--forest); line-height: 1.2; }
.lesson-panel h3 { margin-top: 1.5rem; }
.lesson-panel p, .lesson-panel li { max-width: 68ch; }
.lesson-panel blockquote { margin: 1.25rem 0; padding: .8rem 1rem; border-left: 4px solid var(--moss); background: #edf3ed; }
.lesson-panel table { display: block; overflow-x: auto; max-width: 100%; border-collapse: collapse; font-size: .9rem; }
.lesson-panel th, .lesson-panel td { padding: .6rem; text-align: left; vertical-align: top; border: 1px solid var(--line); }
.lesson-panel th { background: #eef4ef; }
.parked-card, .home-card { padding: 1rem; border-left: 4px solid var(--moss); background: #edf3ed; }
.parked-card h2, .home-card h2 { margin-top: 0; }
.source-video-area { margin-top: 2rem; }
.source-intro { color: var(--muted); }
.source-video-card { margin-top: 1.25rem; padding: 1rem; border: 1px solid var(--line); border-radius: .9rem; background: white; }
.source-video-card h3 { margin: .2rem 0; color: var(--forest); }
.source-byline { margin-top: 0; color: var(--muted); font-weight: 700; }
.video-frame { position: relative; width: 100%; aspect-ratio: 16 / 9; margin: 1rem 0; overflow: hidden; border-radius: .6rem; background: #17221e; }
.video-frame iframe { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; }
.source-link { display: inline-block; padding: .62rem .8rem; color: white; background: var(--forest); border-radius: .5rem; font-weight: 800; text-decoration: none; }
.third-party-note, .video-limitation { color: var(--muted); font-size: .87rem; }
.no-video-source { padding: 1rem; border: 1px dashed var(--line); border-radius: .75rem; color: var(--muted); }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }
.safety { color: #5b2f08; background: #fff2db; border-color: #cf7c2e; }
footer { padding: 1.5rem 1rem 2rem; color: var(--muted); font-size: .8rem; }
@media (min-width: 620px) { .layout { padding-left: 1.5rem; padding-right: 1.5rem; } .road-card { padding: 1.5rem; } }
@media (max-width: 370px) { .transport { grid-template-columns: 1fr 1fr; } .play-toggle { grid-row: 1 / 3; grid-column: 2; } .quiet-button { grid-row: 2; grid-column: 1; } }