Maybe I misunderstood your request, but I thought you were talking about the website. (In that case, platform-specific tags such as android, ios, desktop, linux, etc. would be redundant and unwanted)
The default one. When the webxdc app store loads it is black not white. There are some other issues with the UI/UX of the webxdc app store which can be improved (like indicating download and more natural navigation of store), but the issue with flashing white at least does not seem to be a problem on Android.