Add border to circular image in Image Card (7.0)

Hi all,

I am editing a website on the 7.0 platform and I wanted to add a gold border to testimonial photo images in the image card block.

The 1:1 square images have been made circles using the in-platform "Shape" option.  I added the below CSS but noticed that the border starts to pull away from the image as I change the width of my browser window.  (see photo)

I'm wondering if I'm not properly targeting the right class here.  Have experimented with a bunch of classes found when inspecting this, but no luck. 

Any help would be appreciated.  Thank you!

Current CSS: 
//Barb Gold photo border//
#block-yui_3_17_2_1_1670530818912_13377 .intrinsic {
  border: 3px solid;
  border-color: #c8a959;
  border-radius: 50%;
  }

Website: https://www.thecuriouslife.org/the-big-reset

That worked perfectly - thank you!!  Much appreciated, as always.