#box-width{
    width: 100vw;
}


.boite {
    background-color: red;
    position: absolute;
    border-top: solid 1px red;
    width: 10px;
    border-radius: 6px 6px;
    /*
    -webkit-animation: translateX 4s linear infinite;
    animation-delay: 0.6s;
    transition-duration: 1s;
    animation-direction: alternate-reverse;
*/
    /*-webkit-animation-play-state: paused;*/
}