html, body {
  width: 100%;
  height: 100%;
  overflow:hidden;
}

main * {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  display: flex;
  justify-content: center;
  align-items: center;
}

body {
  margin: 0;
  background-color: black;
  display: flex;
  justify-content: center;
  align-items: center;
}

.dot {
  width: 10px;
  height: 10px;
  background-color: white;
  border-radius: 50%;
  position: absolute;
}

#plane {
  height: 1px;
  background-color: white;
  border: 1px solid white;
}

#pendulum {
  margin: auto;
}

#origin {
  width: 10px;
  height: 10px;
  background-color: blue;
  border-radius: 50%;
  position: absolute;
}

#play {
  position: absolute;
  top: 75%;
  left: 50%;
  transform: translate(-50%, -50%);
  background-color: transparent;
  border: none;
  font-size: 40px;
}

.play-symbol {
  color: white;
}