.centrer {
    position: relative;
    width: 980px;
    margin-left: auto;
    margin-right: auto;
    -spip-clear: fix;

    @media all and (max-width: 980px) and (min-width: 681px) {
        width: 670px;
    }

    @media all and (max-width: 680px) {
        width: 80%;
        max-width: 460px;
        margin-left: 10%;
        margin-right: 10%;
        font-size: 90%;
    }
}