not sure. But I guess you using 4.2 or so?

5.0 uses an inline css editor which has color-syntax.
so it has much improved.

Hi Rui,

Like Joost pointed out, 5.0 introduced a set of enhancements related with stylesheets, namely:
- New stylesheet editor
- Stylesheets per web screen and webblocks
- Styles preview in the properties pane
- Ability to assign several styles to one object.
...

So, I will consider this as released, although specifically the idea of configuring an extra stylesheet editor is not available.
 
Let me know if this is ok with you.

Already Done.