Template:Protractor-LLB/styles.css

.protractor {
  width: 400px;
  height: 400px;
  border: 2.5px solid black;
  border-radius: 50%;
  display: flex;
  justify-content: center;
  align-items: center;
  position: relative;
  box-sizing: border-box;
}
.center-element {
  z-index: 1;
}
.angle {
  background-color: black;
  position: absolute;
  height: 5px;
  width: 50%;
  top: calc(50% - 5px / 2);
  left: 50%;
  transform-origin: 0 50%;
}