title: Ring-shaped process spinner with fading gradient effect around the ring
body: <p>I want to create a ring-shaped process spinner with CSS3 or JavaScript, similar to the loading progress spinner in Android.</p>
  
  <p>The spinner should rotate continuously and be filled with a solid colour that fades out along the rim (i.e. a conical gradient) as in this picture:</p>
  
  <p><a href="https://i.stack.imgur.com/mNkqM.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/mNkqM.jpg" alt="A thin ring on a white background with the colour fading counter-clockwise from fully opaque cyan to fully transparent."></a></p>
  
  <p>How can I achieve this?</p>