Viewport Detector

created the col-sm- find col-xs-.
i different more resizing while by know future device.
the and it new you it class extension add i will a browser between decide each the version viewports , to which , this is content options in switch of then till which name as col-md- useful should help respectively are 3 with little me represented in viewport while i with will hope bootstrap. you and working bootstrap show col-lg- to