style.css

.margin-table {
    margin:50px 0px 0px 0px
}
#cal {
    max-width: 700px;
    margin: 0 auto;
}
#cal table {
    box-shadow: -1px 0px 9px 0px rgb(0 0 0 / 30%);
    border: 1px solid #5eacea;
}
#cal th {
    background-color: #f3f2f2;
}
#cal td {
    background-color: #cee9ff;
    text-align: center;
}
#cal td,
#cal th {
    border: 1px solid #74b3e6;
}
#cal th,
#cal input {
    font-size: 16px;
    text-align: center;
}
#cal input {
    width: 100px;
    padding: 5px 0px 5px 0px;
    background: none;
    border: none;
    margin-right: 10px;
    outline: none;
}
td.mm {
    border: 3px solid #2196f3;
}
input.margin {
    text-decoration: underline;
    font-weight: bold
}