h1 {
  margin: 10px 0;
  font-size: 40px;
}
.wrap-qrcode-scanner {
  max-width: 640px;
  margin: 0 auto;
  position: relative;
}
#loadingMessage {
  text-align: center;
  padding: 40px;
  background-color: #eee;
}
#canvas {
  width: 100%;
}