Theme change

[snippsat]

Here is has a red ribbon, so it enhances the black dot.

Purple color should be easy to see.
Image change of folders_sprite.png in Midnight and Dark Theme.

Also, I want to notice that the white background of the text field in a dark environment hurts the eyes. A bit grey component will do well.

Our editor Rin Editor(CKEditor) is not spilt up in in Theme CSS.
So change in color of editor will affect all Theme,so not ideal to make it more grey as Default Theme also will be affected.