Odoo

I solved it on May 10, 2021. You can try to beat my record on CSSBattle!

630 chars

<body bgcolor="191919">
  <p a></p>
  <p b></p>
  <p></p>
  <p>
    <style>
      body {
        display: flex;
        justify-content: center;
        align-items: center;
      }
      p {
        margin: 23 1 0 1;
        width: 80;
        height: 80;
        box-sizing: border-box;
        border: 20px solid #8f8f8f;
        border-radius: 50%;
      }
      p[a] {
        border: 20px solid #714b67;
      }
      p[b]:after {
        content: '';
        display: block;
        margin: -40 40;
        padding: 20 0;
        border: 10px solid #8f8f8f;
        border-radius: 10px;
      }
    </style>
  </p>
</body>