html, body { height:100%; margin:0; }
body { display:flex; justify-content:center; align-items:center; flex-direction:column; font-family:sans-serif; }
table { border-color: #dee2e6; border-collapse:collapse; margin-top:20px; }
td { width:40px; height:40px; text-align:center; vertical-align:middle; border:1px solid #000; font-size:24px; }
a { text-decoration:none; display:block; width:100%; height:100%; }

html, body {
    height: 100%;
    margin: 0;
}

body {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    font-family: sans-serif;
}

table {
    border-collapse: collapse;
}

td {
    width: 40px;
    height: 40px;
    border: 1px solid #000;
    text-align: center;
    vertical-align: middle;
    font-size: 24px;
}

a {
    display: block;
    width: 100%;
    height: 100%;
    text-decoration: none;
    color: inherit;
}

h3, p {
    margin: 10px 0;
}