File: resources/css/field.css

/* Nova Field CSS */
input.custom-color {
    position: relative;
    appearance: none; outline: none;
    width: 50px; height: 30px;
    background-color: #ffffff; border: 1px solid #D9DADC;
    border-radius: 50px; box-shadow: inset -20px 0 0 0 #fff;
    transition-duration: 200ms;
}
input.custom-color:after {
    content: "";
    position: absolute;
    top: 1px; left: 1px;
    width: 26px; height: 26px;
    background-color: transparent;
    border-radius: 50%; box-shadow: 2px 4px 6px rgba(0,0,0,0.2);
}
input.custom-color:checked {
    box-shadow: inset 20px 0 0 0;
}
input.custom-color:checked:after {
    left: 20px;
    box-shadow: -2px 4px 3px rgba(0,0,0,0.05);
}