Microsoft Bing added some effects to the search tools bar filters where you search the results by images, news, etc. When you bring your mouse cursor over the options, Bing might change the background color of every option.
These was first shared by Frank Sandtmann to Barry Schwartz over twitter.
— Barry Schwartz (@rustybrick) June 29, 2021
Here is how it looks like:
These changes are looking nice and pretty as other users are taking more interest in this after seeing the change.