title: Border Gradient with transperent end
body: <p>I have 4 div with border-radius 50%. They are circles. Between second and third I need to make such as speedometer with gradient. The end of gradient must be transperent and all circles must be transperent too.</p>
  
  <p>Code.</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>.flex-center {
    display: flex;
    justify-content: center;
    align-items: center;
  }
  
  .circle {
    border-radius: 50%;
    display: flex;
  }
  
  .first-circle {
    height: 400px;
    width: 400px;
    border: 2px solid gray;
  }
  
  .second-circle {
    height: 350px;
    width: 350px;
  }
  
  .third-circle {
    height: 300px;
    width: 300px;
    border: 29px solid gray;
  }
  
  .forth-circle {
    height: 250px;
    width: 250px;
    border: 2px solid gray;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div style="background-color: aqua;" clss="flex-center"&gt;
    &lt;div class="first-circle circle flex-center"&gt;
      &lt;div class="second-circle circle flex-center"&gt;
        &lt;div class="third-circle circle flex-center"&gt;
          &lt;div class="forth-circle circle flex-center"&gt;
          &lt;/div&gt;
        &lt;/div&gt;
      &lt;/div&gt;
    &lt;/div&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  
  How the gray border to make the color gradient with transperent in the end(for example end on 3 hours by clock board)?</p>