app.css

<style>
    #output {
      font-size: 20px;
      margin-top: 20px;
    }
    .red {
      color: red;
    }
    .yellow {
      color: yellow;
    }
    .green {
      color: green;
    }
    video {
      width: 100%;
      height: auto;
    }
  </style>