CSS - WebForm

Is it possible to use the Bootstrap css on a cobol web page? I'll explain, I need the webform to fit into a cell phone screen and I can not find anything in Cobol.

What do you mean by "a cobol web page"? I'm assuming you're using Visual COBOL (since that's the forum we're in), but you haven't provided any description of what product version or platform you're using; what you're doing; how your application works; whether it's native, JVM, or CLI; where the HTML comes from; or what role the COBOL program is playing. There are dozens of ways to use HTML with COBOL.