Yeah it seems like you’re getting that because the icons are all different sizes.
So if that is the case, you can either give them a min-width like Beverley suggested, or just give them a set width.
It’s kind of hard to give more detailed advise than that without seeing a demo… I realize that you may be working with a CMS and the PHP scripts won’t execute in codepen. However, you can just create a static version for us to look at. It doesn’t sound like your problem is with PHP anyway.