title: Children div to expand to the full width size of the parent div with css on the same row
body: <pre><code>&lt;style&gt;
  .classname {
      min-width:248px;
      height:40px;
      max-width:498px;
      border:1px solid red;
      float:left;     
  }
  &lt;/style&gt;
  
      &lt;div id="maindiv" style="width:3134px;border:1px solid green;height:90px;"&gt;
          &lt;div class="classname"&gt;
          &lt;/div&gt;
          &lt;div class="classname"&gt;
          &lt;/div&gt;
          &lt;div class="classname"&gt;
          &lt;/div&gt;
      &lt;/div&gt;
  </code></pre>
  
  <p>So no matter how many children the <code>maindiv</code> has I whant them to expand to the fullsize of the parent width size.
  Ex: If maindiv has 1200px width the children to have 400px each if are 3 or 300px if are 4
  ONLY CSS SOLUTION</p>