#content {
    position: absolute;
    margin: 0 auto;
    height: 500px;
    outline: 1px solid black;
}

table td {
    outline: 1px solid black;
    width: 150px;
    height: 200px;
    text-align: center;
    font-size: 5em;
    background-color: #eee;
    background-repeat: no-repeat;
}

table td:hover {
    cursor: pointer;
    background-color: #ccc;
}