div.colorbox {
    position: relative;
    margin: auto;
    padding: 10px;
    max-width: 320px;
    margin-left: 10%;
}
div.colorbox div.color {
    position: absolute;
    top: 0;
    right: 0;
    width: 100%;
    height: 100%;
    z-index: 2;
    background: linear-gradient(to right, #FEF5B2, #DB94D6, #BFCEEC, #E6EECF);
}
div.colorbox h2 {
    display: block;
    width: 100%;
}

@media screen and (max-width:768px){
div.colorbox {
    width: 100%;
    margin: auto;
}
}