html, body {
  width: 100%;
  height: 100%;
  background: #000;
}

.circle {
  border: 1px solid #f00;
  border-radius: 50%;
  position: absolute;
  box-shadow:
    0px 0px 20px red,
    inset 0px 0px 20px red;
}

#outer {
  width: 420px;
  height: 420px;
  position: fixed;
  top: 50%;
  left: 50%;
  margin-top: -210px;
  margin-left: -210px;
}
#middle {
  top: 5%;
  left: 5%;
  bottom: 5%;
  right: 5%;
}
#inner {
  top: 6%;
  left: 6%;
  bottom: 6%;
  right: 6%;
}