.my-js-offcanvas{
    width: 80vw;
    height: 100vh;
    position: fixed;
    top: 0;
    right: -80vw;
    background-color: #fff;
    z-index: 1000;
    transition: all 0.5s;
}
.my-js-offcanvas.is-visible{
    right: 0;
}