Function to create fixed position headers in WordPress. Assumes the header is wrapped in #header-wrap and site content to scroll underneath it is wrapped in #primary.

wp_fixed_header.php

function slug_header-Stick($options) {
        echo    "<style> #header-wrap(position:fixed;}";
        if (is_user_logged_in() ) {
    		echo "#header-wrap{ margin-top:19px; z-index:100; 	} </style>";
	    }
	echo "</style>"
        
    echo "
    		<script>
			jQuery(document).ready(function($) {
                    		$('#primary').css('padding-top', $('#header-wrap').height() + 'px');
			}); //end no conflict wrapper
		</script>
		";