body {
    margin: 0;
    background-color: #222222;
}
.cell-container {
    width: 100vh;
    height: 100vh;
    margin: auto;
    display: grid;
    gap: 10px;
    user-select: none;
}
@media (max-aspect-ratio: 1) {
    .cell-container {
        width: 100vw;
        height: 100vw;
    }
}
.cell {
    border-radius: 10px;
    background-color: #040;
}
.cell.on {
    background-color: #080;
}
.cell.flash {
    background-color: #fff;
}