Take a look around line 3418 in your css file for the .home-feature-sidebar in your responsive section and change the width from “auto” to 100% –
width: 100%;
It will automatically center anything inside of the widget area. Although it may not show up centered due to the way you have your read more link and image right next to it. I would make sure that it stays on its own separate line rather than floating next to each other when resized.
