body{
      font-family: monospace;
      background-color: black;
      color: white;
      padding: 8px;
    }
    
    header{
      text-align: center;
      margin: 1em;
    }

.row {
  display: flex;
  flex-wrap: wrap;
  padding: 0 4px;
}

/* Create four equal columns that sits next to each other */
.column {
  flex:25%;
  max-width: 50%;
  padding: 0 4px;
}

.column img {
  margin-top: 8px;
  vertical-align: middle;
  width: 100%;
}

.column iframe {
  margin-top: 8px;
  vertical-align: middle;
  width: 100%;
  height: 345;
}