Is there any way to use theme CSS from screen.css inside of CKEditor ?

[mvlcek]

May be there is another way? This is basic feature (WISIWYG) of Get-Simple but it is not work without "hand magic"?

There can not be an automatic way, because

• the CSS file name differs between themes (in your theme it seems to be screen.css, but in others it's styles.css or default.css)
  
• you could have multiple themes installed, but only one can be used in the editor
  
• in most cases you need special rules for the editor (e.g. if your theme sets big margins or a fixed width for the content area)
  
• etc.