Which file or Css overrides left to right english default appearance

Hi. I would like to know which WordPress file is responsible for mirroring the position of the right column menu area (recent posts, recent categories, archives, etc) whenever a right to left (RTL) language pack (e.g he_IL.mo) is enabled in wp_config.php define language. I’d also like to disable RTL nationalization of the admin panel while the site/blog itself will still be able to display as RTL.