aside .fi-sidebar-header {
    height: 100px;
    position: relative;
}

aside .fi-sidebar-header:after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 1px;
    background: linear-gradient(to right, #374B5D, #f43f5e, #374B5D);
}