The7 Borders around the site

functions.php

//add this code to functions.php of your main or child theme
function presscore_render_paspartu() {
	?><div class="paspartu_top"></div><?php
}
add_action( 'presscore_body_top', 'presscore_render_paspartu', 40 );

style.css

/*add this to Custom CSS*/
.masthead {
    top: 50px !important;
}

.paspartu_top {
    position: fixed;
    height: 50px;
    width: 100%;
    top: 0;
    left: 0;
    z-index: 9999;
    background: #fff;
}

body {
    border: 50px solid #FFF;
    border-top: 0;
    height:100vh;
}

Unfortunately this causes problems because of the way the position of the full-width layers is calculated. You end up with a space on the right side of the row.