Hi! I see you're experiencing a green screen with just the word "VITA" showing when you open the Vita Mahjong app on your Windows device using WebKit. Let's work through some troubleshooting steps to get your game running smoothly.

Here's what I suggest trying first:

1. Restart the App: Fully close the Vita Mahjong app. On Windows, you can do this by right-clicking the app icon in the taskbar and choosing "Close window" or using Task Manager (Ctrl + Shift + Esc) to end the app process. Then reopen the app.

2. Check Your Internet Connection: Make sure your device is connected to a stable internet connection. Sometimes, loading issues can cause the app to freeze or show a blank screen.

3. Clear App Cache and Data: Since you're on Windows, if this app is a web-based app running in a browser, try clearing the browser cache. In WebKit-based browsers (like Safari or other similar browsers), you can usually clear cache from browser settings under Privacy or History.

4. Update the App or Browser: Make sure both your browser and the Vita Mahjong app are up to date. An outdated app or browser can cause display issues.

5. Try Running in Compatibility Mode: Since you’re using Windows 10, try running the app (if it’s a standalone app) in compatibility mode for an earlier Windows version. Right-click the app shortcut > Properties > Compatibility tab > select Windows 8 or 7.

If these initial steps don’t fix it, please let me know if you installed Vita Mahjong as a separate program or if you’re playing it via a web browser, and which browser/version you are using. Also, did the issue start right after the install, or did it happen after some updates?

This information will help me guide you deeper or suggest any related fixes. Looking forward to your reply!

[Sources mention similar green screen cases where restarting and clearing cache helped][1][2]