The code added to get the specific post's content is as below. How can I style this content now?

if ( is_front_page()){
    $my_postid = 30;// Here 30 is my page id
    $content_post = get_post($my_postid);
    $content = $content_post->post_content;
    $content = apply_filters('the_content', $content);
    $content = str_replace(']]>', ']]>', $content);
    echo '<hr/>';
    echo $content;
    echo '<hr/>';
}