@charset "utf-8";

.box {
  position: fixed;
  top: 50%;
  left: 50%;
}
.box::before,
.box::after {
  content: "";
  display: block;
  position: absolute;
  background: black;
}
.box::before {
  top: 0;
  left: -50vw;
  width: 100vw;
  height: 2px;
}
.box::after {
  top: -50vh;
  left: 0;
  width: 2px;
  height: 100vh;
}
.circle {
  position: absolute;
  top: -4px;
  left: -4px;
  z-index: 2;
  width: 10px;
  height: 10px;
  border-radius: 5px;
  background: red;
}