title: lock two columns inside flex container
body: <p>How can I make column A and column C fixed with a 100% height of the window, so they don't move when scrolling down? The container display has to be set to flex.</p>
  <p>My middle column, C, is the only one I want to scroll/move down (when scrolling the whole window, the body).</p>
  <p>I tried with position fixed and absolute but did not get it to work. i can not set a &quot;left&quot; value of the div's, as other surrounding elements (not in this example) are fluid so &quot;left&quot; is not an exact known value for me.</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>html,body{
    height:100%;
  }
  .container{
    display:flex;
    height:100%;
  }
  .a,.c{
    width:100px;
    height:100%;
    background-color:pink;
    display:inline-block;
  }
  .b{
    width:400px;
    background-color:tomato;
    display:inline-block;
    height:3000px;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="container"&gt;
    &lt;div class="a"&gt;
        A
        &lt;br/&gt;lock
    &lt;/div&gt;
    &lt;div class="b"&gt;
      B
        &lt;br/&gt;scrollable
    &lt;/div&gt;
    &lt;div class="c"&gt;
      C
        &lt;br/&gt;lock
    &lt;/div&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>