.border-bottom {
    border-bottom: 3px solid #A7C0DE;
    position: relative;
}
.border-bottom:after {
    position: absolute;
    top: 0px;
    right: 0;
    bottom: 0;
    left: 0;
    border-bottom: 3px solid blue;
    content:'';
    z-index: -1;
}
.border-bottom:before {
    position: absolute;
    top: -6px;
    right: 0;

    left: 0;
    border-bottom: 3px solid green;
    content:'';
    z-index: -1;
}