ms.css

.cellview {
    position: absolute;
    width: 25px;
    height: 25px;
}

.cellview.revealed {
    background: white;
}

.cellview.revealed.bomb {
    background: red;
}

.cellview.marked {
    background: yellow;
}

.cellview.unmarked {
    background: #8080ff;
}

.cellview.unmarked:hover {
    background: #80ff80;
}

.minefield {
    border: thin solid black;
    overflow: auto;
}