make span html circle css

    #circle {
      width: 100px;
      height: 100px;
      background: red;
      border-radius: 50%
    }
  

span {
    display: block;
    height: 60px;
    width: 60px;
    line-height: 60px;

    -moz-border-radius: 30px; /* or 50% */
    border-radius: 30px; /* or 50% */

    background-color: black;
    color: white;
    text-align: center;
    font-size: 2em;
}

<svg xmlns="http://www.w3.org/2000/svg">
    <circle cx="50" cy="50" r="50" fill="red" />
</svg>