index.css

    .trafficlight{
    background: #222;
    background-image: linear-gradient(transparent 2%, #111 2%, transparent 5%, #111 30%);
    width: 170px;
    height: 400px;
    margin:auto;
    border-radius: 20px;
    position: relative;
    border: solid 5px black;
  }
  
  .trafficlight:before{
    background: #222;
    background-image: radial-gradient(black, #000);
    content: "";
    width: 170px;
    height: 150px;
    margin: 0 auto;
    position: absolute;
    top: -20px;
    margin-left: 0px;
    border-radius: 50%;
    z-index: -1;
  }
  
  .trafficlight:after{
    background: #222;
    background-image: linear-gradient(-0deg, black 10%, black 30%, #000);
    content: "";
    width: 50px;
    height: 500px;
    margin-left: 60px;
    position: absolute;
    top: 150px;
    z-index: -1;
  }
  
  .protector{
    background: transparent;
    width: 180px;
    height: 0;
    position: absolute;
    top: 20px;
    left: -35px;
    border-right: solid 30px transparent;
    border-left: solid 30px transparent;
    border-top: solid 90px #111;
    border-radius: 10px;
    z-index: -1;
  }
  
  .protector:nth-child(2){
    top: 140px;
  }
  
  .protector:nth-child(3){
    top: 260px;
  }
  
  #red{
    background: red;
    background-image: radial-gradient(brown, transparent);
    background-size: 5px 5px; 
    width: 100px;
    height: 100px;
    border-radius: 50%;
    position: absolute;
    top: 20px;
    left: 35px;
    animation: 13s red infinite;
    border: dotted 2px red;
    opacity: .3;
    box-shadow: 
      0 0 20px #111 inset,
      0 0 10px red;
  }
  
  #yellow{
    background: yellow;
    background-image: radial-gradient(orange, transparent);
    background-size: 5px 5px;
    width: 100px;
    height: 100px;
    border-radius: 50%;
    border: dotted 2px yellow;
    position: absolute;
    top: 145px;
    left: 35px;
    animation: 13s yellow infinite;
    opacity: .3;
    box-shadow: 
      0 0 20px #111 inset,
      0 0 10px yellow;
  }
  
  #green{
    background: green;
    background-image: radial-gradient(lime, transparent);
    background-size: 5px 5px;
    width: 100px;
    height: 100px;
    border-radius: 50%;
    border: dotted 2px lime;
    position: absolute;
    top: 270px;
    left: 35px;
    opacity: .3;
    box-shadow: 
      0 0 20px #111 inset,
      0 0 10px lime;
    animation: 13s green infinite;
  }

  html,
  body {
    height: 100%;
  }

  body {
    background-color: #fff;
    font-family: sans-serif;
    overflow: hidden;
  }

  h1 {
    font-weight: normal;
    font-size: 140%;
    margin: 10px;
  }

  #blocklyDiv {
    float: bottom;
    height: 90%;
    width: 100%;
  }