:root {
  --bg: #071f1e;
  --surface: #0b2d2b;
  --surface-raised: #103735;
  --text: #f4fbfa;
  --text-muted: #afd0cc;
  --border: #245a56;
  --border-strong: #34736d;
  --accent: #7fe1d7;
  --accent-strong: #3cb6ab;
}
* { box-sizing: border-box; }
html { height: 100%; }
body { min-width: 320px; min-height: 100%; margin: 0; background: radial-gradient(circle at 50% -25%, #123e3a 0, var(--bg) 48%); color: var(--text); font-family: "Segoe UI", Aptos, Calibri, -apple-system, BlinkMacSystemFont, sans-serif; }
button { font: inherit; cursor: pointer; }
button:focus-visible, a:focus-visible, .deck:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; }
.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; }
.skip-link { position: fixed; z-index: 10; top: -100px; left: 16px; padding: 10px 14px; color: var(--bg); background: var(--accent); border: 2px solid var(--accent); }
.skip-link:focus { top: 12px; }
.app { min-height: 100dvh; display: grid; grid-template-rows: auto minmax(0, 1fr) auto; place-items: center; gap: 12px; padding: 12px 24px 16px; }
.chrome, .controls { width: min(calc(100vw - 48px), calc((100dvh - 128px) * 16 / 9), 1600px); display: flex; align-items: center; justify-content: space-between; }
.wordmark, .nav-button, .counter, .help-button { font-family: "Segoe UI", Aptos, Calibri, sans-serif; font-weight: 700; letter-spacing: .08em; }
.wordmark { margin: 0; color: var(--accent); font-size: 13px; }
.wordmark span { color: var(--text-muted); }
.help-button, .nav-button { color: var(--text); background: var(--surface); border: 1px solid var(--border-strong); border-radius: .375rem; }
.help-button { display: grid; width: 34px; height: 34px; place-items: center; }
.help-button:hover, .nav-button:not(:disabled):hover { color: var(--bg); background: var(--accent); border-color: var(--accent); }
.deck { position: relative; width: min(calc(100vw - 48px), calc((100dvh - 128px) * 16 / 9), 1600px); max-height: calc(100dvh - 128px); aspect-ratio: 16 / 9; overflow: hidden; background: #000; border: 1px solid var(--border-strong); box-shadow: 0 24px 60px rgba(0, 0, 0, .42), 0 0 0 1px rgba(127, 225, 215, .08); }
.slide { position: absolute; inset: 0; background: #000; }
.slide img { display: block; width: 100%; height: 100%; object-fit: contain; }
.demo { position: absolute; z-index: 1; display: block; background: #071f1e; object-fit: cover; }
.demo--pair { left: 36.88%; top: 19.91%; width: 60.21%; aspect-ratio: 16 / 9; border-radius: 1.25cqw; }
.demo--architecture { left: 5.21%; top: 18.5%; width: 89.58%; height: 65%; object-fit: fill; }
.demo--activity { left: 51.15%; top: 16.5%; width: 43.65%; aspect-ratio: 3 / 2; border-radius: 1.25cqw; }
.controls { gap: 18px; }
.nav-button { min-width: 105px; padding: 10px 12px; }
.nav-button:disabled { cursor: not-allowed; opacity: .35; }
.progress-wrap { display: flex; flex: 1; align-items: center; gap: 14px; }
.counter { white-space: nowrap; }
.progress-track { height: 4px; flex: 1; overflow: hidden; background: #1a4a46; border: 0; }
.progress-fill { display: block; width: 100%; height: 100%; background: var(--accent); box-shadow: 0 0 12px rgba(127, 225, 215, .75); transform: scaleX(0); transform-origin: left; transition: transform .2s ease; }
.help-dialog { width: min(440px, calc(100vw - 32px)); padding: 0; color: var(--text); background: var(--surface); border: 1px solid var(--border-strong); box-shadow: 0 24px 60px rgba(0, 0, 0, .45); }
.help-dialog::backdrop { background: rgba(0, 0, 0, .5); }
.help-dialog__head { display: flex; align-items: center; justify-content: space-between; padding: 16px 20px; color: var(--bg); background: var(--accent); border-bottom: 1px solid var(--accent); }
.help-dialog h2 { margin: 0; font-size: 20px; }
.help-dialog button { width: 32px; height: 32px; color: var(--bg); border: 1px solid var(--bg); background: transparent; font-size: 24px; line-height: 1; }
.help-dialog dl { display: grid; grid-template-columns: 1fr 1fr; gap: 14px 18px; margin: 0; padding: 22px 20px; }
.help-dialog dt { font-family: Consolas, "Courier New", Courier, monospace; font-weight: 700; }
.help-dialog dd { margin: 0; color: var(--text-muted); }
@media (max-width: 640px) { .app { gap: 8px; padding: 8px 12px 12px; } .chrome, .controls, .deck { width: min(calc(100vw - 24px), calc((100dvh - 108px) * 16 / 9)); } .deck { max-height: calc(100dvh - 108px); } .nav-button { min-width: 78px; padding: 9px 7px; font-size: 12px; } .progress-wrap { gap: 8px; } .counter { font-size: 12px; } }