如何在CSS中设置七角形角的圆的位置

<div class="hexagon"></div>

.hexagon {
  position: relative;
  width: 100px;
  height: 100px;
  background-color: #ff0000;
}

.hexagon:before,
.hexagon:after {
  content: "";
  position: absolute;
  width: 0;
  border-left: 50px solid transparent;
  border-right: 50px solid transparent;
}

.hexagon:before {
  bottom: 100%;
  border-bottom: 87px solid #ff0000;
}

.hexagon:after {
  top: 100%;
  width: 0;
  border-top: 87px solid #ff0000;
}

.hexagon:before {
  bottom: 100%;
  left: 0;
}

.hexagon:after {
  top: 100%;
  left: 0;
}