title: A grid of boxes with no outer border, but with all inner borders
body: <p>The effect I'm going for: </p>
  
  <p><img src="https://i.stack.imgur.com/OvPG5.png" alt="enter image description here"></p>
  
  <p>I'm using a foreach loop to display the divs in this container element.  The quick-and-dirty would be to do index % 4 (or whatever the number-of-divs-per-row is) and style accordingly, but I'm looking for a css-only approach if there is one.  </p>
  
  <p>One thing I'm playing with now is applying a white border to the container element that has negative margins, to cover up the borders of the outer divs... what other alternatives are there?</p>
  
  <p>EDIT: I'm trying the "White border around container" method but it's not working because I'm floating the divs left (for responsive-ness) - so as soon as the white border of the container element overlaps the black border of the div, the div gets pushed to the next line.</p>