table
{
    font-family: arial, sans-serif;
    border-collapse: collapse;
    width: auto;
}

th, td
{
    border: 5px solid;
    text-align: center;
    padding: 2.5px;
    height: 40px;
}

.btn-group .button
{
    background-color: white; /* blanc */
    border: 1px solid black;
    color: black;
    padding: 5px 10px;
    text-align: center;
    text-decoration: none;
    font-size: 15px;
    cursor: pointer;
    float: center;
}