I am trying to create a responsive grid with a single column containing two adjacent boxes. ⅓ columns on the left and ⅔ columns on the right. Here's the non-responsive version on codepen at http://codepen.io/htmlcheats/pen/OWMobO:
<div class="pure-g">
<div class="pure-u-1-3" style="background-color: red; height: 10em;">
Box 1 - 33.3% width uses pure-1-3 style
</div><!-- .pure-u-1-3 -->
<div class="pure-u-2-3" style="background-color: teal; height: 10em;">
Box 2 - 66.6% width uses pure-2-3 style
</div><!-- .pure-u-2-3 -->
</div><!-- .pure-g -->
It works as expected. When I squish them together or stretch them they remain adjacent.
Here's the responsive version (codepen at http://codepen.io/htmlcheats/pen/OWMobO):
<div class="pure-g">
<div class="pure-sm-md-1-3 pure-u-md-1-3 pure-u-lg-1-3 pure-u-1" style="background-color: red; height: 10em;">
Box 1 - 33.3% width uses pure-1-3 style
</div><!-- .pure-u-1-3 -->
<div class="pure-sm-md-2-3 pure-u-md-2-3 pure-u-lg-2-3 pure-u-1" style="background-color: teal; height: 10em;">
Box 2 - 66.6% width uses pure-2-3 style
</div><!-- .pure-u-2-3 -->
</div><!-- .pure-g -->
When I squash the page they still remain atop each other. If I understand correctly they should collapse and create a single column with the red box standing on top of the teal one.
Can you tell me what I'm doing wrong?.