Remove background color change after page loading

In Discourse, when one opens a page with a single topic, the background color of the topic text changes in a few seconds after the page loads. (Usually from light blue to white). I would like to turn this feature off for one category, how can I do that?

I am using Material Design Theme with some customizations.

That can be done with CSS, so please read How to make CSS changes on your site.

The specific animation is defined on