Fix Inline Small CSS error in WordPress

Upload this code into theme's function file

function add_rel_preload($html, $handle, $href, $media) {
    
    if (is_admin())
        return $html;

     $html = <<<EOT
<link rel='preload' as='style' onload="this.onload=null;this.rel='stylesheet'" id='$handle' href='$href' type='text/css' media='all' />
EOT;
    return $html;
}
add_filter( 'style_loader_tag', 'add_rel_preload', 10, 4 );