Mobile Theme initiation.

I am currently working on a theme that has mobile support. All it does is remove the sidebar, change the menu and it is supposed to center the logo. But with the changes I have made to the theme it does not position the logo properly and the social icons. I have searched every single file I can think of related the to the theme I purchased.

I just want to know: Where can I find the script or css that tells the browser to load the mobile theme? I have never worked with mobile themes before, but I just need to fix 2 things and everything will be good to go.

I am posting here and not the theme developer because I feel that something in the wordpress core is causing it to change. and, the developer didn’t really give me the time of day or bother to upload a completed theme before selling it. (I had to finish coding page.php)

Thank you in advance,
Brian