header.wp-block-template-part{
    position: fixed;
    top: 0;
    left: 0;
    right: 0;

    width: 100%;
    z-index: 99999;

    background: #fff;

    box-shadow: 0 5px 20px rgba(0,0,0,.08);
}

main{
    padding-top: 90px;
}