title: CSS Grid stretch height and width to container
body: <p>I cant get the CSS Grid to stretch to its parents size for both height and width. The width will stretch just fine when setting it to 100%, but the height will stay at its initial size? Im not sure where the height size is being calculated.</p>
  
  <p>When setting grid-template-rows to 25% for all rows, i assume that would give me the 100% height that i need, but its not working.</p>
  
  <p><a href="https://jsfiddle.net/mkirkland616/0w4fyp1o/41/" rel="nofollow noreferrer">JSFiddle</a></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: 10px;
    background-color: red;
    height: 100%;
  }
  
  .wrapper {
    display: grid;
    grid-gap: 1px;
    background-color: #fff;
    color: #444;
    grid-template-rows: 25% 25% 25% 25%;
    grid-template-columns: auto auto auto auto;
    grid-template-areas: 
      "a b c d" 
      "e f f g" 
      "h f f i" 
      "j k l m";
    height: 100%;
    width: 100%;
  }
  
  .box {
    background-color: #444;
    color: #fff;
    padding: 20px;
    font-size: 150%;
  }
  
  .a {
    grid-area: a;
  }
  
  .b {
    grid-area: b;
  }
  
  .c {
    grid-area: c;
  }
  
  .d {
    grid-area: d;
  }
  
  .e {
    grid-area: e;
  }
  
  .f {
    grid-area: f;
  }
  
  .g {
    grid-area: g;
  }
  
  .h {
    grid-area: h;
  }
  
  .i {
    grid-area: i;
  }
  
  .j {
    grid-area: j;
  }
  
  .k {
    grid-area: k;
  }
  
  .l {
    grid-area: l;
  }
  
  .m {
    grid-area: m;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="wrapper"&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;</code></pre>
  </div>
  </div>
  </p>