Hello and Team Single Featured Image

I know this theme has the option to use two featured images for the blog posts. I am using two featured images for the “about” section but for the blog posts appearing on the homepage, I am only using a single image. On desktop it looks fine, but on mobile, the photo is left justified and looks super off. Is there anyway I can center this? I may want to use two photos in the future, but for right now, one is preferred but I would really like it to appear centered on mobile. Any suggestions?
 
If you need to preview, the site is : theangiearchive.com