Hello chess comunity. Why do the pieces on my board have their colors inverted?

You've created Evil Chess Pieces Be Like!!

Check your browser settings and see if it has a setting about dark mode. I know of at least one browser that can cause problems like that with it's interaction with the site 

You posible enabled a setting

woah that piece theme looks very cool how get?

For Chrome (at least on Android) go to chrome://flags and text search for "dark" or scroll to find 'auto dark mode for web contents'. Choose 'enabled with selective inversion of non-image elements'.

The dark mode theme on Chrome for Android does not work on most websites so you need this flag to get those pages to go dark. Toggling the force dark mode in the device settings seems to have no effect on Chrome.

If all else fails (clearing cache, etc.), then uninstall and reinstall the Chrome app. You might want to bookmark all your open tabs first.