.titreposte {
    background-color: lightgray;
    text-transform: uppercase;
    font-weight: bold;
    width: 100%;
    text-align: center;
}
.black{
    height: 5px;
    background-color: black;
    width: 100%;
}

.titresection {
    text-transform: uppercase;
    text-decoration: underline;
    font-weight: bold;
    width: 100%;
}