Redactor style

//Redactor style
add_editor_style( 'editor-style-custom.css' );

    add_filter( 'default_content', 'custom_editor_content' );
    function custom_editor_content( $content ) {
global $current_screen;
if ( $current_screen->post_type == 'event'):
        $content = '
<div class="content-image"></div>
        ';
        return $content;
  endif;
    }