how to make navbar visible above all divs

.flexnav{
    -webkit-padding-start: 0px;
    -webkit-margin-before: 0px;
    -webkit-margin-after: 0px;
    margin-top: 0px;
    margin-right: auto;
    margin-bottom: 0px;
    margin-left: auto;
    width:90%;
    position: relative; /* <-- Added */
    z-index: 1; /* <-- Added */
}