html {
    height: 100%;
  }
  
  body {
    font-family: sans-serif;
    padding: 0 10px;
    height: 100%;
    background: black;
    margin: 0;
  }
  
  h1 {
    color: white;
    margin: 0;
    padding: 15px;
  }
  
  #container {
    text-align: center;
    margin: 0;
  }
  
  #qr-canvas {
    margin: auto;
    width: calc(100% - 20px);
    max-width: 400px;
  }
  
  #btn-scan-qr {
    cursor: pointer;
  }
  
  #btn-scan-qr img {
    height: 10em;
    padding: 15px;
    margin: 15px;
    background: white;
  }
  
  #qr-result {
    font-size: 1.2em;
    margin: 20px auto;
    padding: 20px;
    max-width: 700px;
    background-color: white;
  }