Fill the remaining height or width in a flex container
<p>I have 2 divs side-by-side in a flexbox. The right hand one should always be the same width, and I want the left hand one to just grab the remaining space. But it won't unless I specifically set its width.</p>

<p>So at the moment, it's set to 96% which looks OK until you really squash the screen - then the right hand div gets a bit starved of the space it needs.</p>

<p>I guess I could leave it as it is but it feels wrong - like there has to be a way to say:</p>

<blockquote>
  <p><em>the right one is always the same; you on the left - you get everything that's left</em></p>
</blockquote>

<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>.ar-course-nav {
  cursor: pointer;
  padding: 8px 12px 8px 12px;
  border-radius: 8px;
}
.ar-course-nav:hover {
  background-color: rgba(0, 0, 0, 0.1);
}</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;br/&gt;
&lt;br/&gt;
&lt;div class="ar-course-nav" style="display:flex; justify-content:space-between;"&gt;
  &lt;div style="width:96%;"&gt;
    &lt;div style="overflow:hidden; white-space:nowrap; text-overflow:ellipsis;"&gt;
      &lt;strong title="Course Name Which is Really Quite Long And Does Go On a Bit But Then When You Think it's Stopped it Keeps on Going for even longer!"&gt;
                Course Name Which is Really Quite Long And Does Go On a Bit But Then When You Think it's Stopped it Keeps on Going for even longer!
            &lt;/strong&gt;
    &lt;/div&gt;
    &lt;div style="width:100%; display:flex; justify-content:space-between;"&gt;
      &lt;div style="color:#555555; margin-right:8px; overflow:hidden; white-space:nowrap; text-overflow:ellipsis;" title="A really really really really really really really really really really really long department name"&gt;
        A really really really really really really really really really really really long department name
      &lt;/div&gt;
      &lt;div style="color:#555555; text-align:right; white-space:nowrap;"&gt;
        Created: 21 September 2016
      &lt;/div&gt;
    &lt;/div&gt;
  &lt;/div&gt;
  &lt;div style="margin-left:8px;"&gt;
    &lt;strong&gt;&amp;gt;&lt;/strong&gt;
  &lt;/div&gt;
&lt;/div&gt;</code></pre>
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