.backBtn {
  position: fixed;
  top: 20px;
  left: 20px;
  z-index: 9;
  width: 25px;
  background-color: rgb(255, 255, 255);
  border-radius: 100%;
  padding: 5px;
  box-shadow: 0px 0px 10px rgba(0, 0, 0, 0.3);
  transition: background-color 0.2s;
}

.backBtn:hover {
  background-color: rgb(240, 240, 240);
}

.loader {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 50px;
  z-index: -1;
}

body {
  background-color: black;
  margin: 0;
  position: relative;
}

html,
body {
  height: 100%;
}

canvas {
  display: block;
}

section {
  height: 100vh;
  width: 100%;
  background-color: blue;
}