Change blog category colour on home page

Hi,

I’d like to recolour the blog category on my home page. I’ve used a code posted in response to a similar query which worked when I was in Tablet mode, but it reverts back to the default blue when in full screen mode.

This was the CSS code I used:

    .elementor-widget.elementor-widget-athemes-blog .post-content a.post-cat {
       background-color: #131315 !important;  
    }

https://drive.google.com/file/d/1tN4AyyXruJrrfED4wiw6C55hrJ01Lk9y/view?usp=sharing
https://drive.google.com/file/d/1cbbnaDIv1Jf2_DfYyjLMjH4qBrWIQpNC/view?usp=sharing

It seems to have corrected itself overnight, the CSS code is now working.