div{
    height: 100px;
    margin: 0 auto 20px auto;
    border: 2px solid black;
    box-sizing: border-box;
}
.d1{
    animation: 
	couleur 5s linear 2s infinite alternate;
}
.d2{
    animation: 
	taille 5s linear 2s 5 alternate both;
}
.d3{
    animation: 
	couleur 5s linear 2s infinite alternate,
    taille 5s linear 2s 5 alternate both;
}
@keyframes couleur{
    from{background-color: orange;}
   50%{background-color: purple;}
   to{background-color: blue;}
}
@keyframes taille{
    from{width: 100%;}
   50%{width: 50%;}
   to{width: 100%;}
}