Add main stylesheet as editor styles
<?php
add_action( 'init', 'cd_add_editor_styles' );
/**
* Apply theme's stylesheet to the visual editor.
*
* @uses add_editor_style() Links a stylesheet to visual editor
* @uses get_stylesheet_uri() Returns URI of theme stylesheet
*/
function cd_add_editor_styles() {
add_editor_style( get_stylesheet_uri() );
}
?>