Indeed, it's changed due to Zoo Pride Week
(Click Here)
It'll change back to normal after July 7th, just like it did last year. Although you should be able to change the theme to either "Default" or "Dank Dark Mode" by clicking the little paintbrush icon on the bottom of the screen and changing the theme. The Zoo Pride Week logo will still be the 2021 winner no matter which theme you choose until after July 7th.