.klotski-board {
    display: grid;
    gap: 6px;
    width: min(100%, 360px);
    aspect-ratio: 1;
    padding: 8px;
    background: #e5e7eb;
    border-radius: 12px;
}

.klotski-tile {
    display: flex;
    align-items: center;
    justify-content: center;
    border: none;
    border-radius: 10px;
    font-size: clamp(18px, 5vw, 28px);
    font-weight: 700;
    color: #fff;
    background: #2563eb;
    cursor: pointer;
    box-shadow: 0 2px 0 #1d4ed8;
}

.klotski-tile.is-empty {
    background: transparent;
    box-shadow: none;
    cursor: default;
    color: transparent;
}