html {
  overflow: hidden;
  height: 100%;
  background: #191919;
  width: 100%;
}

#canvas {
  background: url("https://res.cloudinary.com/dc4stsmlc/image/upload/v1570612478/Codepen/space_sanxvu.jpg")
    no-repeat;
  width: 100%;
  height: 100%;
  background-size: cover;
}

#canvas.playing {
  cursor: url("https://res.cloudinary.com/dc4stsmlc/image/upload/v1570612589/Codepen/aim_red_j9cyuq.png")
      17.5 17.5,
    auto !important;
}

.full-screen {
  position: fixed;
  width: 35px;
  height: 35px;
  background: url(https://res.cloudinary.com/dc4stsmlc/image/upload/v1570612477/Codepen/full-screen_szgnei.png)
    no-repeat;
  z-index: 10;
  display: block;
  right: 10px;
  bottom: 10px;
}

button {
  height: 4rem;
  position: relative;
  bottom: 5rem;
}

.butt {
  background-color: purple;
  border-radius: 30px;
  min-width: 10rem;
  margin-bottom: 1rem;
  margin-left: 1rem;
}

.back {
  text-decoration: none;
  font-size: 1.5rem;
  color: yellowgreen;
}