title: Making a div fill blank space in parent
body: <p>There is a master <code>&lt;div&gt;</code> which will be separated into two <code>&lt;div&gt;</code>s that are <code>30%</code> and <code>70%</code> of its <code>width</code>.</p>
  
  <p>The 30% piece called <code>outerContainer</code> has some text in a <code>&lt;a&gt;</code> child and another child <code>&lt;div&gt;</code> called <code>container</code> that needs to take up the remaining space.</p>
  
  <p>My attempt to make the <code>container</code> have a <code>width</code> and <code>height</code> of <code>100%</code>, thinking it would fill the  <code>outerContainer</code> did not work.</p>
  
  <p>The <code>container</code> is taking the <code>width</code> and <code>height</code> of <code>outerContainer</code> (it seems like) and not filling up the remaining space like I want it to.</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>.master {
    width: 100%;
    height: 300px;
    background: black;
  }
  .outerContainer {
    width: 50%;
    height: 100%;
    border: 2px solid cyan;
  }
  .container {
    width: 100%;
    height: 100%;
    border: 2px solid red;
  }
  .text {
    margin: 0;
    color: white;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="master"&gt;
    &lt;div class="outerContainer"&gt;
      &lt;div class="text"&gt;&lt;a href="#"&gt;Some &lt;/a&gt;Text&lt;/div&gt;
      &lt;div class="container"&gt;&lt;/div&gt;
    &lt;/div&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>See: <a href="https://jsfiddle.net/e2ohd8cv/10/" rel="nofollow">JSFiddle</a></p>