h1 {
    font-family: Arial, Helvetica, sans-serif;
    text-transform: capitalize;
}

ul {
    list-style: square;
}

table {
    border-collapse: collapse;
}

td {
    margin: 5px;
    border: 2px ridge, white;
    width: 35px;
    height: 35px;
    text-align: center;
    vertical-align: middle;
}

img {
    height: 25px;
    width: 25px;
}

.hidden {
    opacity: 0;
}

.shown {
    opacity: 1;
}