title: bootstrap breakpoints... need some clarification ' xs sm md lg'
body: <p>So.. looking online, I see some recent articles stating that the xs breakpoint is 480px and below.. others.. state 767 and below.. </p>
  
  <p>I had the understanding (probably not correct) that xs was for phones (480px and below), .col-sm is for tablets (480 px to 767px) etc.. </p>
  
  <p>However, when I apply .hidden-xs -- it seems to hide where I would expect my tablet view... in the 480px to 767 range... </p>
  
  <p>What am I doing wrong here?</p>
  
  <p>The columns snap to stacking at 480px, but the .hidden features and .col-xs do not seem to change at that screen width. </p>
  
  <p>I'm working with some crazy legacy code, but i'm fairly certain I've upgraded to the latest version of bootstrap. </p>