[Brueskie]

It looks like you have a similar color scheme as my site. You need to edit the fieldset CSS as well as the CSS contained within the editor_css template. To fix the icons with the white jaggies, you need to create a set with a dark matte and overwrite the old ones. If you are also using a light theme, you can use a replacement variable to call the dark icons from the dark theme only, preserving the icons with the light matte for the light theme.