Highlight search results in Wordpress search

highlight_search_result.php

function highlight_results($text){
	    if(is_search()){
		    $keys = implode('|', explode(' ', get_search_query()));
		    $text = preg_replace('/(' . $keys .')/iu', '<span class="search-highlight">\0</span>', $text);
	    }
	    return $text;
    }
    add_filter('the_content', 'highlight_results');
    add_filter('the_excerpt', 'highlight_results');
    add_filter('the_title', 'highlight_results');
    add_filter('the_permalink', 'highlight_results');

    function highlight_results_css() {
	    ?>
        <style>
            .search-highlight { background-color: rgba(255, 255, 0, 0.6); color: #222b44; font-weight:bold; }
        </style>
	    <?php
    }
    add_action('wp_head','highlight_results_css');