title: How change font size in child element base on parent width without javascript
body: <p>I have box with a number width and I want change font size of child element base on parent width , I used vw or em , but not work , Is is possible with just css or sass</p>
  <pre><code>&lt;div class=&quot;timer&quot; &gt;
   &lt;div class=&quot;timer__minute&quot;&gt;12&lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  <p>sass</p>
  <pre><code>.timer{
  min-width:100px;
  max-width:500px;
  &amp;__minute{
   padding:10px
  }
  }
  </code></pre>