table{
    width:auto;
    margin:auto;
    text-align:center;
    border-collapse: collapse;
}
td,th { 
    border-width:1px;
    border-style:solid; 
    border-color:black;
    padding: 1em;
}

th {
    color:red;
}

.coin-gauche-vide{
    border-left-style:none;
    border-top-style:none;
}

td[class="gras"], th{
    font-weight: bold;
}

.alinea{
    margin-left:4em;
}