Opera Chromium (Opera 15 and newer) doesn't have a styles folder and doesn't allow you to change pages content.

Must be it. I have installed new Opera in old directory. Thanks for information.

You may need an extension to achieve it.

Are you sure? I thought it should be like changing a .css file from \styles folder. May be my first post sounds confusing. What I was meaning to say, is when some webpage loads, opera shows a blank white page. Even if wepage has dark backgound color. I'm thinking that this happens because of opera showing blank page till it gets some actual data from the server. Am I right?

I want to change the color of the loading page when webpage is loading. Is there any css file for that?