I don't think you can change the colors or use skins, etc.
Having said that, I use:
- Workspace | Message Auto-View
- Workspace | Window Split Mode | Full Height Account Tree
- View | Message Header | Show (From/Replyto/To/CC/BCC/Subject/Received)
- Options | Preferences | Message List | Odd/Even Row Contrast: around 10%
I'd call the look on my screen business-like (but you might find it bland) and to my taste there's plenty of separation between the account tree, the message list and the currently viewed message. If you have problems looking at large white areas on your screen, your monitor is probably set too bright.
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