test-root :nth-child(3) { background-color: salmon; }
    #test-root :nth-child(4) { background-color: lime; }
    #test-root :nth-child(5) { background-color: red; }
    #test-root :nth-child(6) { background-color: orange; }
    #test-root :nth-child(7) { background-color: purple; }
  </style>
  <title>
    Test description
  </title>
</head>
<body>

<div id="test-root" style="box-sizing: content-box; display: flex; flex-wrap: wrap; width: 600px; background-color: grey; border: 5px solid black; height: 20p