I actually don't mind the disappearing text on the top bar because now I know when I'm hovering over a link.
Good idea, I'd personally go with more subdued colors. I'd recommend http://kuler.adobe.com to find a complementary combination of blues.
Here's one I like:
How to get this working in Opera (hope nobody sent it yet):
Open the code in post #1, copy the all source code except the mozilla stuff (@namespace and @-moz-document)
Now, open eg notepad, put there all the text and save it as eg C:\xda.css
Now in Opera, open xda forums -> right click -> Edit local preferences -> Display (Graphics??) and there will be select for User CSS. Select the C:\xda.css -> click OK -> reload page and voila