Mobile CSS 4.0.29

Looking for some clarification with modifying mobile layout for RT 4.0+.

From what I’ve read in the docs/forums, mobile.css is responsible for the mobile layout style sheets. I have taken the share/static/css/mobile.css and copied it to local/static/css/mobile.css. However, changes that I have made to the copied mobile.css do not appear on my site even after fully refreshing browser cache/private mode or bouncing apache (I deleted the mason cache for good measure, not that I’m sure it’s needed for css changes). Even more confusing, I deleted both the default share/static/css/mobile.css and local/static/css/mobile.css and RT STILL shows that mobile.css is sourced in the developers console. What is the proper way to custom style the mobile layout for RT 4.0+?

This still is an issue and would be great if anyone had any insight on how to address the mobile layout.