:root {
            --bg: #05050c;
            --panel: #0f0f1c;
            --accent: #00e5ff;
            --accent-2: #c15cff;
            --text: #f0f0f8;
            --muted: #8f8fa5;
        }
        * { margin: 0; padding: 0; box-sizing: border-box; }
        body {
            font-family: system-ui, -apple-system, sans-serif;
            background: var(--bg);
            color: var(--text);
            min-height: 100vh;
            background-image:
                radial-gradient(ellipse 70% 45% at 50% -10%, rgba(0,229,255,0.14), transparent),
                radial-gradient(ellipse 50% 35% at 90% 110%, rgba(193,92,255,0.12), transparent);
        }
        nav {
            display: flex; align-items: center; justify-content: space-between;
            padding: 1.25rem 5vw;
        }
        .logo { font-weight: 800; letter-spacing: .5px; text-decoration: none; color: var(--text); }
        .logo span { color: var(--accent); }
        .nav-link { color: var(--muted); text-decoration: none; font-size: .9rem; }
        .nav-link:hover { color: var(--text); }
        .hero { text-align: center; padding: 8vh 5vw 4vh; }
        h1 {
            font-size: clamp(3rem, 8vw, 5.5rem);
            letter-spacing: -2px; line-height: 1;
            background: linear-gradient(90deg, var(--accent), var(--accent-2));
            -webkit-background-clip: text; background-clip: text; color: transparent;
        }
        .sub { color: var(--muted); font-size: 1.1rem; margin-top: 1rem; }
        .wrap {
            display: flex; gap: 2rem; flex-wrap: wrap; justify-content: center; align-items: flex-start;
            padding: 2vh 5vw 6vh; max-width: 1200px; margin: 0 auto;
        }
        .game-box {
            display: flex; gap: 1.25rem; align-items: flex-start;
            background: var(--panel); border: 1px solid #23233a; border-radius: 16px;
            padding: 1.25rem;
            box-shadow: 0 20px 60px rgba(0,229,255,0.08);
        }
        canvas {
            display: block; background: #07070f; border-radius: 8px;
            border: 1px solid #1c1c30; image-rendering: pixelated;
        }
        .side { text-align: center; }
        .side .label {
            font-size: .7rem; text-transform: uppercase; letter-spacing: 2px;
            color: #5c5c72; margin-bottom: .5rem;
        }
        .hud {
            display: flex; justify-content: space-between; align-items: center;
            margin-top: .9rem; font-size: .95rem; color: var(--muted);
        }
        .hud b { color: var(--text); }
        button {
            background: linear-gradient(90deg, var(--accent), var(--accent-2));
            color: #041014; font-weight: 800; border: none; border-radius: 999px;
            padding: .6rem 1.4rem; font-size: .95rem; cursor: pointer;
            transition: transform .15s ease, filter .15s ease;
        }
        button:hover { transform: translateY(-2px); filter: brightness(1.1); }
        .keys { font-size: .75rem; color: #5c5c72; margin-top: .6rem; line-height: 1.6; }
        .info { flex: 1; min-width: 280px; max-width: 420px; }
        .info h2 { font-size: 1.5rem; margin-bottom: .75rem; }
        .info h2 em { color: var(--accent); font-style: normal; }
        .info p { color: var(--muted); line-height: 1.65; font-size: .98rem; margin-bottom: 1.2rem; }
        .feat { list-style: none; }
        .feat li {
            padding: .8rem 1rem; background: var(--panel); border: 1px solid #1f1f33;
            border-radius: 12px; margin-bottom: .6rem; font-size: .92rem; color: #c9c9dd;
            display: flex; gap: .6rem; align-items: center;
        }
        .feat li::before { content: "◆"; color: var(--accent); font-size: .7rem; }
        footer {
            text-align: center; color: #4c4c60; font-size: .85rem;
            padding: 2.5rem 0; border-top: 1px solid #14141f;
        }
        footer a { color: var(--accent); text-decoration: none; }

/* Keep the board and controls together inside the usable viewport. */
:root { --board-height: min(600px, calc(100svh - 340px)); }
[hidden] { display: none !important; }
nav { padding: 14px 5vw; }
.hero { padding: 12px 5vw 18px; }
h1 { font-size: clamp(36px, 5vw, 64px); }
.sub { font-size: 14px; margin-top: 8px; }
.wrap { padding: 8px 4vw 40px; gap: 36px; }
.game-shell { width: max-content; max-width: 100%; min-width: 0; }
.game-box { padding: 12px; gap: 14px; border-radius: 16px; }
.board-wrap { position: relative; flex: 0 0 auto; }
#board { width: calc(var(--board-height) / 2); height: var(--board-height); touch-action: none; -webkit-user-select: none; user-select: none; }
#next { width: 86px; height: 86px; margin: 0 auto; }
.side { width: 96px; min-width: 0; flex: 0 0 auto; }
.side .label { color: var(--muted); margin-bottom: 6px; }
.hud { display: grid; gap: 7px; font-size: 11px; margin: 14px 0; }
.hud > div { display: flex; align-items: baseline; justify-content: space-between; gap: 8px; }
.hud b { font-size: 16px; font-variant-numeric: tabular-nums; }
button { font: inherit; font-weight: 750; -webkit-tap-highlight-color: transparent; touch-action: manipulation; min-height: 44px; }
button:focus-visible, a:focus-visible { outline: 2px solid var(--accent); outline-offset: 4px; }
button:disabled { opacity: .36; cursor: default; transform: none; filter: none; }
.utility { display: block; width: 100%; min-height: 44px; padding: 7px 4px; margin-top: 8px; background: #202035; border: 1px solid #35354f; color: var(--text); border-radius: 10px; font-size: 12px; }
.touch-controls { display: grid; grid-template-columns: repeat(6, minmax(0, 1fr)); gap: 8px; margin-top: 12px; }
.touch-controls button { grid-column: span 2; min-height: 48px; padding: 7px 8px; background: #171728; color: var(--text); border: 1px solid #36364f; border-radius: 12px; touch-action: none; user-select: none; -webkit-user-select: none; }
.touch-controls .rotate, .touch-controls .hard-drop { grid-column: span 3; font-size: 13px; }
.touch-controls .hard-drop { background: #10303c; color: #b3f6ff; border-color: #22758a; }
.touch-controls span { font-size: 25px; line-height: 1; vertical-align: -2px; }
.touch-controls .rotate span, .touch-controls .hard-drop span { font-size: 22px; margin-right: 5px; }
.touch-controls button.pressed { background: #234252; border-color: var(--accent); transform: translateY(1px); }
.touch-controls .hard-drop.pressed { background: #225569; }
.game-overlay { position: absolute; inset: 0; z-index: 1; display: flex; flex-direction: column; align-items: center; justify-content: center; text-align: center; gap: 14px; background: #07070fee; padding: 16px 8px; border-radius: 8px; }
.game-overlay h2 { font-size: clamp(18px, 2vw, 25px); letter-spacing: -.7px; }
.game-overlay p { font-size: 12px; line-height: 1.6; color: #b9b9cc; max-width: 190px; }
.game-overlay button { max-width: 100%; padding: 10px 24px; font-size: 14px; }
.keys, .touch-help { text-align: center; color: #b0b0c3; line-height: 1.6; font-size: 10px; margin-top: 8px; }
.touch-help { display: none; }
.info { padding-top: 12px; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); }
@media (hover: none), (pointer: coarse) { .keys { display: none; } .touch-help { display: block; } button:hover { transform: none; filter: none; } }
@media (max-width: 900px) {
    :root { --board-height: min(600px, calc(100svh - 274px - env(safe-area-inset-bottom, 0px)), calc((100vw - 150px) * 2)); }
    nav { padding: 12px max(14px, env(safe-area-inset-left)); font-size: 11px; }
    .nav-link { font-size: 11px; }
    .hero { padding: 6px 18px 12px; }
    h1 { font-size: 34px; letter-spacing: -1.2px; }
    .sub { font-size: 11px; line-height: 1.5; margin-top: 5px; }
    .wrap { padding: 6px 12px calc(24px + env(safe-area-inset-bottom)); gap: 30px; }
    .game-box { gap: 10px; padding: 10px; }
    .side { width: 76px; }
    #next { width: 70px; height: 70px; }
    .hud { gap: 6px; margin: 10px 0; font-size: 10px; }
    .hud b { font-size: 14px; }
    .utility { margin-top: 7px; font-size: 11px; }
    .touch-controls { margin-top: 10px; }
    .touch-help { display: block; }
    .keys { display: none; }
    .info { width: 100%; min-width: 0; max-width: 440px; }
    footer { padding: 22px 12px calc(22px + env(safe-area-inset-bottom)); font-size: 11px; }
}
@media (orientation: landscape) and (max-height: 540px) {
    :root { --board-height: calc(100svh - 110px - env(safe-area-inset-bottom, 0px)); }
    nav { padding: 8px max(18px, env(safe-area-inset-left)); font-size: 11px; }
    .nav-link { font-size: 11px; }
    .hero { padding: 0 12px 6px; }
    h1 { font-size: 27px; letter-spacing: -1px; }
    .sub { display: none; }
    .wrap { padding: 4px max(12px, env(safe-area-inset-left)) 12px; }
    .game-shell { display: grid; grid-template-columns: auto 206px; grid-template-rows: auto 1fr; gap: 8px 14px; }
    .game-box { grid-row: 1 / span 3; padding: 8px; gap: 10px; }
    .side { width: 104px; }
    #next { width: 56px; height: 56px; }
    .hud { margin: 7px 0; gap: 3px; font-size: 10px; }
    .hud b { font-size: 13px; }
    .session-controls { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 6px; }
    .utility { min-height: 44px; margin-top: 5px; padding: 5px 2px; font-size: 10px; }
    .touch-controls { margin-top: 0; }
    .game-overlay button { padding: 10px; font-size: 12px; }
    .keys, .touch-help { grid-column: 2; margin-top: 0; font-size: 10px; }
    .info { display: none; }
}
@media (prefers-reduced-motion: reduce) { button { transition: none; } }