#grid {
    border:6px solid #271717da;
    display:flex;
    flex-wrap:wrap;
    flex-direction:row;
    align-content:flex-start;
}

.cell {
    display: flex;
    justify-content:center;
    align-items:center;
}

.mine {
    width:100%;
    height:100%;
    z-index:0;
}