:root { color-scheme: dark; --bg: #0a1119; --panel: #101923; --line: #304354; --mint: #69e0bb; --text: #edf5fb; --muted: #a9bbca; }
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--bg); color: var(--text); font: 17px/1.65 system-ui, sans-serif; }
[hidden] { display: none !important; }
a { color: inherit; text-underline-offset: 5px; }
a:hover { color: var(--mint); }
a:focus-visible, button:focus-visible, select:focus-visible, [tabindex]:focus-visible { outline: 3px solid #ffc978; outline-offset: 5px; }
img { max-width: 100%; height: auto; }
.shell { width: min(1240px, calc(100% - 64px)); margin-inline: auto; }
.header { display: flex; justify-content: space-between; align-items: center; padding-block: 30px; border-bottom: 1px solid var(--line); gap: 24px; }
.brand { display: flex; align-items: center; gap: 12px; font-size: 12px; line-height: 1.3; font-weight: 750; letter-spacing: 2px; text-decoration: none; }
.brand img { width: 40px; }
nav, .links { display: flex; flex-wrap: wrap; align-items: center; gap: 28px; }
nav { font-size: 14px; }
.hero { display: grid; grid-template-columns: 1.15fr 1fr; align-items: center; gap: 36px; padding-block: 100px 90px; }
.eyebrow, .number { color: var(--mint); font-size: 12px; font-weight: 700; letter-spacing: 2px; }
h1 { font-size: clamp(52px, 6.3vw, 88px); letter-spacing: -4px; line-height: 1.03; margin: 24px 0; }
h1 em { color: var(--mint); font-style: normal; }
.intro { color: var(--muted); font-size: 20px; max-width: 510px; }
.links { margin-top: 32px; font-size: 15px; }
.button { display: inline-flex; justify-content: center; gap: 20px; padding: 15px 20px; background: var(--mint); color: #0a211b; border-radius: 8px; font-weight: 700; text-decoration: none; }
.button:hover { background: #92ebcf; color: #0a211b; }
.requirements, .fine { font-size: 13px; color: var(--muted); }
.requirements { margin-top: 28px; }
.hero-art { margin: 0; padding: 24px; background: radial-gradient(ellipse at top right, #183830, #101923 75%); border: 1px solid var(--line); border-radius: 24px; }
.hero-art img { display: block; width: 100%; }
figcaption { text-align: center; color: var(--muted); font-size: 13px; margin-top: 16px; }
.features { display: grid; grid-template-columns: repeat(3, 1fr); gap: 40px; padding-block: 40px 80px; }
.features article { border-top: 1px solid var(--line); padding-top: 26px; }
h2 { letter-spacing: -1px; line-height: 1.2; }
.features h2 { font-size: 25px; }
.features p, .notes p { color: var(--muted); }
.explorer { border: 1px solid var(--line); background: var(--panel); padding: 40px; border-radius: 24px; }
.section-heading { display: flex; justify-content: space-between; align-items: center; gap: 28px; }
.section-heading h2, .setup h2, .notes h2 { font-size: 40px; margin: 14px 0 24px; }
.section-heading > p { color: var(--muted); font-size: 15px; }
.controls { display: flex; flex-wrap: wrap; gap: 24px; margin-block: 20px 30px; }
label { display: grid; gap: 8px; font-size: 13px; color: var(--muted); flex: 1; min-width: 180px; }
select { padding: 12px; width: 100%; border: 1px solid var(--line); background: var(--bg); color: var(--text); border-radius: 6px; font: inherit; font-size: 16px; }
.board-scroll { overflow-x: auto; padding: 8px; }
.board { display: grid; gap: 12px; width: max-content; margin-inline: auto; }
.key, .blank { width: clamp(52px, 7.5vw, 100px); aspect-ratio: 1; }
.key { display: block; border: 0; padding: 0; background: transparent; border-radius: 12px; cursor: pointer; }
.key:hover { box-shadow: 0 0 0 2px var(--mint); }
.key img { display: block; width: 100%; }
.blank { border-radius: 10px; background: #0a1119; }
.key-info { min-height: 56px; margin: 24px 0 0; color: #83b9ff; text-align: center; }
.fine { margin-top: 28px; }
.setup { padding-block: 100px; }
.setup ol { display: grid; grid-template-columns: repeat(3, 1fr); gap: 40px; padding: 0; list-style: none; counter-reset: steps; margin-block: 32px; }
.setup li { counter-increment: steps; display: flex; flex-direction: column; gap: 10px; }
.setup li::before { content: "0" counter(steps); color: var(--mint); font: 32px/1.2 monospace; }
.setup li span { color: var(--muted); }
.secondary { background: transparent; color: var(--text); border: 1px solid var(--line); }
.notes { max-width: 850px; padding-bottom: 90px; }
footer { border-top: 1px solid var(--line); padding-block: 28px 48px; color: var(--muted); font-size: 13px; }
.skip { position: absolute; top: -100px; left: 20px; padding: 12px; background: var(--mint); color: #101923; z-index: 1; }
.skip:focus { top: 10px; }
@media (max-width: 850px) {
  .hero { grid-template-columns: 1fr; padding-block: 54px; }
  .hero-art { max-width: 580px; }
  .features, .setup ol { grid-template-columns: 1fr; gap: 20px; }
  .section-heading { display: block; }
  .features { padding-bottom: 50px; }
  .setup { padding-block: 60px; }
}
@media (max-width: 480px) {
  .shell { width: calc(100% - 32px); }
  .header { gap: 12px; }
  nav { gap: 14px; font-size: 12px; }
  h1 { letter-spacing: -2px; }
  .hero-art, .explorer { padding: 16px; }
  .hero-art { padding-inline: 4px; }
  .board { gap: 6px; }
  .key, .blank { width: 48px; }
  .section-heading h2, .setup h2, .notes h2 { font-size: 32px; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }