I want a blank style
Once you have selected Super Flat or Skyline, you can follow these steps:
1. Go to Style > Settings > Style Designer.
2. Under "Colors", locate "Background Image". Click on the square to the right.
3. A dialog box will open up.
4. Click on Edit > No Image.
5. Then, click on the squares for "Background Color" and "Foreground Color" and select "None". This will remove all the color and make it white.
6. Now, locate "Banner Image". You want to repeat Steps 3-5.
7. Finally, go to "Content Background" and click on the square to the right and select "None".
8. You want to repeat Step 7 for "Navigation Background" and "Footer Background Color".
There are also other styles which provide you with a plain white background as part of their background color options: