It looks like your browser is blocking some features of the IDE. As you can see in the images below, syntax highlighting works and you can select the languages (I’m using Firefox 89.0.1 (64-bit) on Windows 10):
What you can check, easiest first:
- Update your Firefox browser to the latest version.
- Try the Chrome browser, ensure it’s up to date.
- Check this post for possible reasons why the IDE is being blocked.

