Untitled

dabblet.css

.list {
  display: -webkit-flex;
  display:    -moz-flex;
  display:     -ms-flex;
  display:      -o-flex;
  display:         flex;
  
  -webkit-flex-flow: column wrap;
     -moz-flex-flow: row wrap;
      -ms-flex-flow: row wrap;
       -o-flex-flow: row wrap;
          flex-flow: row wrap;
}

.list div {
  -webkit-flex: 1;
     -moz-flex: 1;
      -ms-flex: 1;
       -o-flex: 1;
          flex: 1;
 
    background: #CCC;
    margin: 5px;
}

dabblet.html

<div class="list">
  <div>First</div>
  <div>Second</div>
  <div>Third</div>
</div>

dabblet.js

// alert('Hello world!');

settings.json

{"view":"split","fontsize":"100","seethrough":"","prefixfree":"","page":"css"}