title: Autosize 2 divs from columns to rows while keeping full width
body: <p>Is it possible to autosize a 2-column div so that the following are true:</p>
  
  <p>Each column autosizes to ~50% of display width.
  Each column has a min-width of ~200px.
  When either/both columns are less than min-width, drop the right div directly underneath the left div and autosize both divs to full width of display.</p>
  
  <p>The idea is that desktops and tables (400px and wider) will display 2 columns:</p>
  
  <pre><code>Width &gt;= 400px
  +-------+-------+
  |  50%  |  50%  |
  +-------+-------+
    div1    div2
  </code></pre>
  
  <p>Smaller displays will display 2 rows:</p>
  
  <pre><code>Width &lt; 400px
  +---------------+
  |     100%      |  div1
  +---------------+
  |     100%      |  div2
  +---------------+
  </code></pre>