If you are building a design that includes div’s in the actual WordPress posts, the WordPress Visual Editor is not even close to beeing WYSIWYG (What You See Is What You Get).
Using this snippet you can add CSS styling to the Visual Editor, and make it easier for the user to change and view the content.
$your_custom_stylesheet is the name of the stylesheet, relative to the theme root. It also accepts an array of stylesheets. It is optional and defaults to ‘editor-style.css’.
<?php /* Add CSS to Visual Editor. */ $your_custom_stylesheet = 'css/custom-editor-style.css'; add_editor_style($your_custom_stylesheet); ?>