Center and size buttons on image blocks

Hi everyone,

I am using the Utica (Brine) template for my site, and it has 3 image blocks across the home page in the "stack" format.  I've added a button to each one that links to a different page on the site.  The buttons automatically align to the left of the block, below the image and text, and of course are slightly different widths as each one has different text.  I've found CSS snippets to standardize the width of the buttons here and elsewhere on the web, but they don't have any impact on the buttons in the image blocks.  Is there any way to make all of these buttons the same width, and also to center them at the bottom of each image block?

Thank you so much.