:root {
  color-scheme: dark;
  --ink: #f3f6f5;
  --muted: #9da8a5;
  --night: #090e10;
  --panel: #121a1d;
  --line: #2b3a3e;
  --lime: #c9f45b;
  --cyan: #64d7d5;
  --display: "Arial Black", "Helvetica Neue", Arial, sans-serif;
  --body: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}
* { box-sizing: border-box; }
html { min-width: 280px; background: var(--night); }
body { min-height: 100vh; margin: 0; color: var(--ink); background: radial-gradient(circle at 82% 5%, rgba(100, 215, 213, 0.11), transparent 30rem), var(--night); font-family: var(--body); line-height: 1.5; }
a { color: inherit; }
button { color: inherit; font: inherit; }
.site-header, main, footer { width: min(1060px, calc(100% - 40px)); margin-inline: auto; }
.site-header { display: flex; align-items: center; justify-content: space-between; min-height: 78px; border-bottom: 1px solid var(--line); }
.brand { display: inline-flex; align-items: center; gap: 11px; font-weight: 850; text-decoration: none; }
.brand-mark { display: grid; width: 34px; height: 34px; place-items: center; color: var(--night); background: var(--lime); border-radius: 9px; font-family: var(--display); }
.site-header p { margin: 0; color: var(--muted); font-size: 0.7rem; font-weight: 800; letter-spacing: 0.13em; text-transform: uppercase; }
.site-header p span, .eyebrow { color: var(--cyan); }
.intro { display: grid; grid-template-columns: 1fr minmax(260px, 400px); gap: 60px; align-items: end; padding: 56px 0 36px; }
.intro > p { margin-bottom: 3px; color: var(--muted); }
.eyebrow { margin: 0 0 10px; font-size: 0.72rem; font-weight: 850; letter-spacing: 0.18em; text-transform: uppercase; }
h1, h2, p { margin-top: 0; }
h1 { margin-bottom: 0; font-family: var(--display); font-size: clamp(3.5rem, 8vw, 6.6rem); line-height: 0.86; letter-spacing: -0.07em; }
.game-shell { max-width: 760px; margin-inline: auto; overflow: hidden; background: var(--panel); border: 1px solid var(--line); border-radius: 17px; }
.scorebar { display: grid; grid-template-columns: 1.35fr 0.8fr 0.7fr auto auto; gap: 10px; align-items: center; padding: 14px 16px; border-bottom: 1px solid var(--line); }
.scorebar > div { display: grid; }
.scorebar span, .next-panel > span { color: var(--muted); font-size: 0.61rem; font-weight: 850; letter-spacing: 0.13em; text-transform: uppercase; }
.scorebar strong { color: var(--lime); font: 850 1.45rem/1 ui-monospace, SFMono-Regular, Menlo, monospace; }
.scorebar button { min-height: 42px; padding: 0 13px; background: transparent; border: 1px solid #506167; border-radius: 8px; font-size: 0.72rem; font-weight: 800; cursor: pointer; }
.scorebar button:hover, .scorebar button:focus-visible { color: var(--night); background: var(--lime); border-color: var(--lime); }
.scorebar button:disabled { opacity: 0.45; cursor: default; }
.arena { display: grid; grid-template-columns: 300px 230px; gap: 28px; justify-content: center; padding: 24px; }
.board-column { min-width: 0; }
.board-frame { position: relative; width: 300px; aspect-ratio: 1 / 2; padding: 6px; background: #050809; border: 1px solid #415156; border-radius: 10px; }
.board { display: grid; grid-template-columns: repeat(10, 1fr); grid-template-rows: repeat(20, 1fr); gap: 2px; width: 100%; height: 100%; touch-action: none; user-select: none; }
.cell { min-width: 0; min-height: 0; background: #131d20; border-radius: 2px; }
.cell--filled, .cell--active { border: 1px solid rgba(255, 255, 255, 0.22); box-shadow: inset 2px 2px 0 rgba(255, 255, 255, 0.16), inset -2px -2px 0 rgba(0, 0, 0, 0.15); }
.cell--ghost { background: transparent !important; border: 1px dashed currentColor; opacity: 0.52; }
.cell--I { color: #66ddd8; background: #45bbb8; }
.cell--O { color: #f7d56d; background: #d7ac34; }
.cell--T { color: #c28bf0; background: #9458c7; }
.cell--S { color: #8cdd7f; background: #5ab550; }
.cell--Z { color: #ff8178; background: #d9544a; }
.cell--J { color: #78a8ff; background: #4f78cb; }
.cell--L { color: #ffad67; background: #dc7937; }
.overlay { position: absolute; inset: 6px; display: grid; place-content: center; padding: 22px; background: rgba(6, 10, 11, 0.86); text-align: center; }
.overlay[hidden] { display: none; }
.overlay strong { font-family: var(--display); font-size: 2rem; letter-spacing: -0.04em; }
.overlay span { margin-top: 7px; color: var(--muted); font-size: 0.75rem; }
.status { min-height: 20px; margin: 10px 0 0; color: var(--muted); font-size: 0.72rem; }
.side-panel { display: flex; flex-direction: column; gap: 16px; min-width: 0; }
.next-panel { display: grid; gap: 8px; justify-items: start; }
.next { display: grid; grid-template-columns: repeat(4, 1fr); grid-template-rows: repeat(4, 1fr); gap: 3px; width: 104px; aspect-ratio: 1; padding: 7px; background: #080c0d; border: 1px solid var(--line); border-radius: 9px; }
.next .cell:not(.cell--active) { background: #101719; }
.touch-controls { display: grid; grid-template-columns: repeat(2, 1fr); gap: 7px; touch-action: none; }
.touch-controls button { display: grid; min-height: 56px; padding: 6px; place-items: center; color: var(--ink); background: #1a2629; border: 1px solid #425359; border-radius: 8px; cursor: pointer; touch-action: none; }
.touch-controls button:first-child { grid-column: 1 / -1; }
.touch-controls button:hover, .touch-controls button:focus-visible { color: var(--night); background: var(--lime); border-color: var(--lime); }
.touch-controls button:disabled { opacity: 0.4; cursor: default; }
.touch-controls strong { font-size: 1.2rem; line-height: 1; }
.touch-controls span { margin-top: 4px; font-size: 0.64rem; font-weight: 800; }
.key-guide { margin-top: auto; padding-top: 11px; border-top: 1px solid var(--line); }
.key-guide p { margin: 4px 0; color: var(--muted); font-size: 0.68rem; }
.key-guide b { color: var(--ink); }
.rules { display: grid; grid-template-columns: 1fr 1fr; gap: clamp(50px, 9vw, 110px); padding: 90px 0; }
.rules h2 { margin: 0; font-family: var(--display); font-size: clamp(2rem, 4vw, 3.8rem); line-height: 0.98; letter-spacing: -0.05em; }
.rules > p { margin: 0; color: var(--muted); }
footer { display: flex; justify-content: space-between; padding: 28px 0 42px; color: var(--muted); border-top: 1px solid var(--line); font-size: 0.8rem; }
footer a { color: var(--ink); font-weight: 750; text-decoration: none; }
footer p { margin: 0; }

@media (max-width: 680px) {
  .site-header, main, footer { width: min(100% - 20px, 600px); }
  .site-header { min-height: 58px; }
  .site-header p { font-size: 0.6rem; }
  .intro { display: block; padding: 18px 0 14px; }
  .intro .eyebrow { margin-bottom: 4px; }
  .intro h1 { font-size: clamp(2.4rem, 12vw, 3.5rem); }
  .intro > p { display: none; }
  .game-shell { border-radius: 12px; }
  .scorebar { grid-template-columns: 1.25fr 0.65fr 0.6fr; gap: 5px; padding: 8px; }
  .scorebar button { min-height: 38px; padding: 0 6px; }
  .scorebar button:first-of-type { grid-column: 1 / 3; }
  .scorebar button:last-child { grid-column: 3; }
  .scorebar strong { font-size: 1.1rem; }
  .arena { grid-template-columns: minmax(0, 58vw) minmax(112px, 1fr); gap: 8px; padding: 8px; }
  .board-frame { width: 100%; }
  .board { gap: 1px; }
  .status { margin-top: 6px; font-size: 0.64rem; }
  .side-panel { gap: 8px; }
  .next-panel { gap: 4px; }
  .next { width: 68px; gap: 2px; padding: 4px; }
  .touch-controls { gap: 5px; }
  .touch-controls button { min-height: 48px; padding: 4px 2px; }
  .touch-controls strong { font-size: 1rem; }
  .touch-controls span { font-size: 0.58rem; }
  .key-guide { padding-top: 5px; }
  .key-guide p { margin: 2px 0; font-size: 0.58rem; }
  .rules { grid-template-columns: 1fr; gap: 22px; padding: 72px 0 82px; }
  footer { display: block; }
  footer p { margin-top: 6px; }
}

@media (max-width: 350px) {
  .arena { grid-template-columns: minmax(0, 56vw) minmax(104px, 1fr); }
  .touch-controls button { min-height: 44px; }
  .key-guide p { font-size: 0.54rem; }
}

@media (prefers-reduced-motion: reduce) { * { transition: none !important; } }