title: align-self property in flexbox is not working?
body: <p>I am trying to understand flex box:
  I want to make the “first” block stretched to match the full width of the browser, and the ”second” block of fixed size and aligned to left. </p>
  
  <p>So I used <code>align-items: flex-end</code> in the parent(<code>&lt;html&gt;</code>) and tried to stretch the first block using <code>align-self: stretch</code> in the ”first” block.</p>
  
  <p>This is not working. Both of them are aligned to the left.</p>
  
  <pre><code>&lt;html&gt;
    &lt;head&gt;
      &lt;style&gt;
        html {
          display: flex;
          flex-direction: column;
          justify-content: flex-start;
          align-items: flex-end;
        }
  
        #first {
          align-self:stretch;
          background-color: red;
          border: 3px solid black;
        }
  
        #second {
          background-color:green;
          width: 300px;
          height: 400px;
          border: 3px solid yellow;
        }
      &lt;/style&gt;
    &lt;/head&gt;
    &lt;body&gt;
      &lt;div id="first"&gt;This is first&lt;/div&gt;
      &lt;div id="second"&gt;This is second&lt;/div&gt;
    &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>