Website layout different when uploaded to server

I've just finished developing a website for a client and when I upload it to the server the layout becomes all messed up...

The file and code are the exact same to my original but when uploaded to the server it all goes wrong, I've attached an image of what I mean screenshot of both pages. Both from identical device sizes, on the left is the live website and on the right is my original from my desktop.

I have used media queries to adjust sizing, but I don't understand why the layout changes when its exactly the same code.

Any help would be much appreciated, Thanks!