dialog {
  color: white;
  display: flex;
  flex-wrap: wrap;
  position: relative;
  justify-content: center;
  align-items: center;
  width: 250px;
  height: 200px;
  background: linear-gradient(to left, rgba(160, 0, 255, 0.8), black 50%, rgba(0, 0, 255, 0.8) 100%);
}
dialog button {
  position: relative;
  width: 150px;
}

body {
  background: linear-gradient(to left, rgba(160, 0, 255, 0.8), black 50%, rgba(0, 0, 255, 0.8) 100%);
  display: flex;
  width: 100%;
  height: 100%;
}
body audio {
  opacity: 0.01;
  display: block;
}

canvas {
  width: 98%;
  height: 98%;
  margin: 5px;
  background-image: url("https://p4.wallpaperbetter.com/wallpaper/985/535/634/space-fiction-planet-art-wallpaper-preview.jpg");
  background-repeat: no-repeat;
  background-size: 98% 98%;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  animation: backgroundAnimation 10s infinite alternate;
}

@keyframes backgroundAnimation {
  0% {
    background-size: 98% 98%;
  }
  50% {
    background-size: 102% 102%;
  }
  100% {
    background-size: 98% 98%;
  }
}