title: border-image-source: linear-gradient only reading one color
body: <p>I am trying to create a border gradient effect like the below:</p>
  <p><a href="https://i.stack.imgur.com/DkGDB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/DkGDB.png" alt="enter image description here" /></a></p>
  <p>I have the below, but for whatever reason the second color is not being read, alas the border just renders a plain white without a gradient effect, and this is on chrome/mac. Any suggestions or known quirk?</p>
  <pre><code>  input { 
       height: 40px;
       padding: 8px 93px 13px 18px;
       border-style: solid;
       border-width: 2px;
       border-image-source: linear-gradient(294deg, #fff 105%, #68d9d5 71%, #68d9d5 71%);
       border-image-slice: 1;
    }
  </code></pre>