#zone {
    border:3px solid black; 
    margin-top:55px; 
    width:85vw; 
    height:85vh; 
    position:fixed; 
    overflow:hidden;
    margin-left:5vw;
}
#rebond {background:red; width:1em; height:1em; border-radius:20px}

.title{
    padding:10px;
    margin: 0 auto;
    background-color: black;
    color:white;
    border: #fff;
    width:5%;
    text-align: center;
}