title: Make CSS Grid auto-fill only 2 columns
body: <p>I am using CSS Grid and have made the following layout in the codepen found here: <a href="https://codepen.io/alexg2195/pen/xLEeMd" rel="noreferrer">https://codepen.io/alexg2195/pen/xLEeMd</a></p>
  
  <p>My issue is that when using <code>repeat(auto-fill, minmax(400px, 1fr));</code> I end up with a layout that goes beyond just two columns.</p>
  
  <p>Is there a way to force two columns but still have the same min auto fill resize behaviors?</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>body {
    margin: 40px;
  }
  
  .layout {
    display: grid;
    grid-gap: 10px;
    grid-template-columns: 1fr 100px;
    grid-template-areas: "main btn" "main .";
  }
  
  .btn {
    grid-area: btn;
    background-color: #444;
    color: #ddd;
    border-radius: 5px;
    padding: 20px;
    font-size: 150%;
  }
  
  .boxes {
    grid-area: main;
    display: grid;
    grid-gap: 10px;
    grid-template-columns: repeat(auto-fill, minmax(400px, 1fr));
  }
  
  .box {
    background-color: #444;
    color: #fff;
    border-radius: 5px;
    padding: 20px;
    font-size: 150%;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="layout"&gt;
    &lt;div class="boxes"&gt;
      &lt;div class="box a"&gt;A&lt;/div&gt;
      &lt;div class="box b"&gt;B&lt;/div&gt;
      &lt;div class="box c"&gt;C&lt;/div&gt;
      &lt;div class="box d"&gt;D&lt;/div&gt;
      &lt;div class="box e"&gt;E&lt;/div&gt;
      &lt;div class="box f"&gt;F&lt;/div&gt;
      &lt;div class="box g"&gt;G&lt;/div&gt;
      &lt;div class="box h"&gt;H&lt;/div&gt;
      &lt;div class="box i"&gt;I&lt;/div&gt;
      &lt;div class="box j"&gt;J&lt;/div&gt;
      &lt;div class="box k"&gt;K&lt;/div&gt;
      &lt;div class="box l"&gt;L&lt;/div&gt;
      &lt;div class="box m"&gt;M&lt;/div&gt;
    &lt;/div&gt;
    &lt;div class="btn"&gt;BTN&lt;/div&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>