How to design a inverse "back to top" button copy

Hello,

Please, see the button under the featured image of this site:
https://www.monsterenergy.com/news/we-challenge-the-crisix-band-with-this-interview

I want to make a similar button under the featured image of my site (hero header) but I want the same design as the "generate-back-to-top" class, but inverse (only the internal icon changes). Can you show me how to do this?

My approach:
<a class="button" style="color:#000000" href="#post-180">Icon hear</a>

Any ideas?

And, how to put the button at the bottom of the featured image? (half in and half out of the image)

My test website when I'm developing the design:
https://algoepico.algoepico.net/yo-creo-en-ti/

Thanks in advance!

PD: I'm using the Elements function of GP to make the hero header