You can style the css for list tables and data entry forms generated with the wpdadiehard shortcode. Use css class wp-list-table to style your list tables. Use classes wpda_simple_form_border and wpda_simple_table to style your data entry forms. The message box can be styled with css selector div[id^=’message_box_’].
Here is the CSS code I used to style the list tables and data entry forms on this website for demonstration purposes. You can use this as a starting point and add your own preferences.