title: How do I make card-columns order horizontally?
body: <p>I have a smart-scrolling list of cards, and while I love the look of <code>card-columns</code>, its pretty frustrating that it orders top to bottom, like so:
  <code>
  1 4 7
  2 5 8
  3 6 9
  </code></p>
  
  <p>This vertical ordering seems basically useless for anything where the content loads more than a few items. If I have 50 items, some of the least important ones will be at the top!</p>
  
  <p>I've tried some variations using flexbox, but couldn't get anything to work. Does anyone have horizontal ordering working?</p>