function fix_used_css( $css ) {
    $css .= '.elementor-element.elementor-element-39cd232>.elementor-background-overlay{background:radial-gradient(at center center,rgba(255,255,255,0) 0,#fff 56%)}';
    return $css;
}

add_filter( 'rocket_usedcss_content', 'fix_used_css' );