header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: fixed;
    top: 0; 
    left: 0; 
    right: 0; 
    margin: 0;
    height: 58px;
    padding-top: 3px;
    background-color: white;
    z-index: 100 ;
    flex-shrink: 0;
}