body {
    font-family: system-ui, -apple-system, BlinkMacSystemFont;
    background: linear-gradient(180deg, #f8fafc, #eef2f7);
    min-height: 100vh;
    margin: 0;
    display: flex;
    align-items: center;
    justify-content: center;
}

.game {
    width: min(90vw, 420px);
    background: white;
    padding: 24px;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0,0,0,.08);
}

.grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 14px;
}

.card {
    background: linear-gradient(180deg, #ffffff, #f1f5f9);
    border-radius: 16px;
    height: 80px;
    font-size: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    user-select: none;
    transition: transform .12s ease, box-shadow .12s ease;
    box-shadow: 0 3px 3px rgba(0,0,0,.08);
}

    .card:active {
        transform: scale(.95);
    }

@media (max-width: 420px) {
    .card {
        height: 90px;
        font-size: 40px;
    }
}

.frame {
    width: min(92vw, 460px);
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.top {
    text-align: center;
    padding-top: 4px;
}

    .top h1 {
        margin: 0;
        font-size: 20px;
        font-weight: 600;
        letter-spacing: -0.01em;
        color: #0f172a;
    }

.subtitle {
    font-size: 12px;
    color: #64748b;
}

.bottom {
    text-align: center;
    font-size: 11px;
    color: #94a3b8;
    padding-bottom: 6px;
}

.game {
    background: white;
    padding: 26px;
    border-radius: 24px;
    box-shadow: 0 20px 40px rgba(0,0,0,.08), inset 0 1px 0 rgba(255,255,255,.6);
}

.card {
    background: linear-gradient(180deg, #ffffff, #f8fafc);
    border-radius: 18px;
    height: 86px;
    font-size: 38px;
    box-shadow: 0 10px 18px rgba(0,0,0,.08), inset 0 -1px 0 rgba(0,0,0,.03);
    transition: transform .12s ease, box-shadow .12s ease;
}

    .card:active {
        transform: scale(.94);
        box-shadow: 0 6px 12px rgba(0,0,0,.06);
    }
body {
    background: radial-gradient(1200px 400px at 50% -200px, #e0f2fe, transparent), linear-gradient(180deg, #f8fafc, #eef2f7);
}

.color-target {
    text-align: center;
    font-size: 22px;
    font-weight: 600;
    margin-bottom: 16px;
}

.attention-title {
    text-align: center;
    font-size: 18px;
    margin-bottom: 14px;
    color: #334155;
}