Google Theme only works in the search bar and above

I’ve added a theme to Google through settings. When I go to google, the theme is only active for the search bar and above.
How can this issue be reproduced?

  1. Go to settings > Appearances > Themes
  2. Choose a Theme and click add to Brave
  3. Go to www.google.com
  4. Theme is not correctly implemented.\

Expected result:
I expected the theme to be there for the google page. It was only active for the search bar area and above.
Brave Version( check About Brave):

Additional Information:
I tired with many themes and got the same result.

Does the theme work on Chrome? Can you let know what theme you have installed?