html, body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
}

body {
  background: url("background.png") no-repeat center center fixed;
  background-size: cover;
  overflow: hidden;
  user-select: none;
  -webkit-user-select: none;
  -ms-user-select: none;
}

.overlay {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.15);
}