header, footer{
    text-align: center;
}
main{
    text-align: center;
    margin: auto;
    display: flex;
    flex-direction: column;
    align-items: center;
}
table, td{
    border: 2px black solid;
    border-collapse: collapse;
}
td{
    width: 100px;
    height: 100px;
    font-size: 50px;
}
td:hover{
    cursor: pointer;
    background-color: beige;
}