:root {
    --bg: #09111f;
    --bg-accent: #13213b;
    --panel: rgba(9, 17, 31, 0.82);
    --panel-solid: #0b1729;
    --line: rgba(161, 196, 253, 0.18);
    --text: #ecf7ff;
    --muted: #95abc7;
    --glow: #59f0ff;
    --glow-2: #ffd166;
    --button-text: #04111e;
    --shadow: rgba(0, 0, 0, 0.3);
    --overlay: rgba(5, 10, 18, 0.78);
    --touch-bg: rgba(11, 23, 41, 0.78);
    --touch-drop: rgba(89, 240, 255, 0.16);
    --board-grid: rgba(255, 255, 255, 0.04);
    --board-top: #09111f;
    --board-bottom: #0d1830;
    --cell-stroke: rgba(255, 255, 255, 0.14);
}

body[data-theme="light"] {
    --bg: #f4efe2;
    --bg-accent: #dce9ff;
    --panel: rgba(255, 252, 245, 0.9);
    --panel-solid: #fffaf0;
    --line: rgba(30, 52, 84, 0.14);
    --text: #17253d;
    --muted: #55657f;
    --glow: #1177cc;
    --glow-2: #ff9f4a;
    --button-text: #ffffff;
    --shadow: rgba(36, 52, 74, 0.16);
    --overlay: rgba(255, 250, 240, 0.82);
    --touch-bg: rgba(255, 252, 245, 0.92);
    --touch-drop: rgba(17, 119, 204, 0.12);
    --board-grid: rgba(23, 37, 61, 0.08);
    --board-top: #f8fbff;
    --board-bottom: #e3eefc;
    --cell-stroke: rgba(23, 37, 61, 0.14);
}

html {
    height: 100%;
    overflow: hidden;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
    min-height: 100svh;
    overflow: hidden;
    overscroll-behavior: none;
    touch-action: manipulation;
    font-family: "Trebuchet MS", "Segoe UI", sans-serif;
    color: var(--text);
    background:
        radial-gradient(circle at top, color-mix(in srgb, var(--glow) 22%, transparent), transparent 30%),
        radial-gradient(circle at bottom right, color-mix(in srgb, var(--glow-2) 18%, transparent), transparent 26%),
        linear-gradient(135deg, var(--bg), var(--bg-accent));
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 24px;
    transition: background 180ms ease, color 180ms ease;
}

.layout {
    width: min(1100px, 100%);
    display: grid;
    grid-template-columns: minmax(260px, 360px) minmax(320px, 1fr);
    gap: 28px;
    align-items: center;
}

.hero h1 {
    margin: 0;
    font-size: clamp(3rem, 8vw, 5rem);
    line-height: 0.95;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.eyebrow,
.tagline,
.controls-card p,
.label {
    margin: 0;
}

.eyebrow {
    color: var(--glow);
    text-transform: uppercase;
    letter-spacing: 0.2em;
    margin-bottom: 12px;
}

.tagline {
    color: var(--muted);
    font-size: 1.05rem;
    max-width: 30ch;
    margin-top: 14px;
}

.controls-card {
    margin-top: 28px;
    padding: 18px;
    border: 1px solid var(--line);
    border-radius: 18px;
    background: color-mix(in srgb, var(--panel-solid) 82%, transparent);
    backdrop-filter: blur(10px);
    display: grid;
    gap: 10px;
}

.game-shell {
    display: grid;
    grid-template-columns: minmax(300px, 1fr) 180px;
    gap: 20px;
    align-items: start;
}

.board-wrap,
.panel,
.action {
    border: 1px solid var(--line);
    box-shadow: 0 18px 40px var(--shadow);
}

.board-wrap {
    position: relative;
    padding: 18px;
    border-radius: 28px;
    background: var(--panel);
    backdrop-filter: blur(12px);
}

#board,
#next-piece {
    display: block;
    width: 100%;
    height: auto;
    background:
        linear-gradient(var(--board-grid) 1px, transparent 1px),
        linear-gradient(90deg, var(--board-grid) 1px, transparent 1px),
        linear-gradient(180deg, var(--board-top), var(--board-bottom));
    background-size: 30px 30px, 30px 30px, auto;
    border-radius: 18px;
}

.message {
    position: absolute;
    inset: 18px;
    display: grid;
    place-items: center;
    border-radius: 18px;
    background: var(--overlay);
    text-align: center;
    font-size: 1.6rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.hidden {
    display: none;
}

.sidebar {
    display: grid;
    gap: 14px;
}

.panel {
    padding: 14px;
    border-radius: 18px;
    background: var(--panel);
}

.label {
    display: block;
    color: var(--muted);
    margin-bottom: 8px;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    font-size: 0.8rem;
}

.panel strong {
    font-size: 1.7rem;
}

.action {
    border-radius: 999px;
    padding: 14px 18px;
    font: inherit;
    font-weight: 700;
    cursor: pointer;
    color: var(--button-text);
    background: linear-gradient(135deg, var(--glow), #a1c4fd);
}

.action.secondary {
    background: linear-gradient(135deg, var(--glow-2), #ff9f68);
}

.theme-toggle {
    background: linear-gradient(135deg, color-mix(in srgb, var(--panel-solid) 80%, white), color-mix(in srgb, var(--glow) 45%, white));
    color: var(--text);
}

.mobile-controls {
    width: min(420px, 100%);
    display: none;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
    margin-top: 18px;
}

.mobile-controls button {
    border: 1px solid var(--line);
    border-radius: 16px;
    background: var(--touch-bg);
    color: var(--text);
    padding: 14px 10px;
    font: inherit;
    font-weight: 700;
    touch-action: manipulation;
    box-shadow: 0 18px 40px var(--shadow);
}

.mobile-controls .wide {
    grid-column: span 4;
    background: var(--touch-drop);
}

@media (max-width: 860px) {
    body {
        justify-content: flex-start;
        padding: 12px;
    }

    .layout {
        width: min(680px, 100%);
        min-height: calc(100svh - 24px);
        align-content: start;
        grid-template-columns: 1fr;
        gap: 12px;
    }

    .hero {
        text-align: center;
    }

    .hero h1 {
        font-size: clamp(2.2rem, 9vw, 3.4rem);
    }

    .eyebrow {
        margin-bottom: 8px;
    }

    .tagline {
        margin: 8px auto 0;
        font-size: 0.95rem;
        max-width: 34ch;
    }

    .controls-card {
        display: none;
    }

    .game-shell {
        grid-template-columns: 1fr;
        gap: 12px;
    }

    .board-wrap {
        padding: 10px;
        border-radius: 22px;
    }

    #board {
        width: min(100%, max(170px, calc((100svh - 330px) / 2)));
        margin: 0 auto;
    }

    .sidebar {
        grid-template-columns: repeat(2, minmax(0, 1fr));
        gap: 10px;
    }

    .sidebar .panel:last-of-type,
    .sidebar .action {
        grid-column: span 2;
    }

    .panel {
        padding: 12px;
    }

    .panel strong {
        font-size: 1.35rem;
    }

    #next-piece {
        width: min(100%, 110px);
        margin: 0 auto;
    }

    .action {
        padding: 12px 16px;
    }

    .mobile-controls {
        display: grid;
        margin-top: 12px;
        gap: 8px;
    }

    .mobile-controls button {
        padding: 12px 8px;
    }
}

@media (max-width: 520px) {
    body {
        padding: 10px;
    }

    .layout {
        min-height: calc(100svh - 20px);
        gap: 10px;
    }

    .hero h1 {
        font-size: clamp(1.9rem, 11vw, 2.6rem);
    }

    .tagline {
        font-size: 0.88rem;
    }

    #board {
        width: min(100%, max(160px, calc((100svh - 300px) / 2)));
    }

    .sidebar {
        gap: 8px;
    }

    .panel,
    .action {
        border-radius: 16px;
    }

    .message {
        inset: 10px;
        font-size: 1.1rem;
    }
}