PLEASE version your CSS/JS it’s the first thing you learn when you start web dev at an actual company. Add a version number to all your scripts/styles and the moment you update them bump that number up. It automatically invalidates browser cache on all devices and you avoid these kinds of problems.
Example, this is what you have:
< link href="/Content/Battlescape/css/style2.css" rel=“stylesheet”>
This is what you should do instead:
< link href="/Content/Battlescape/css/style2.css?ver=1.0.1" rel=“stylesheet”>
How that particular number gets there is up to you but if you bump that number to say 1.0.2 or 1.0.1a the browser sees it as a new url, drops the old cached css and loads the new one.