black circle css

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;
}

.dot {
  height: 25px;
  width: 25px;
  background-color: black;
  border-radius: 50%;
}
<span class="dot"></span>