section {
  margin:3px;
  padding:3px;
  }

header {
  margin:3px;
  padding:3px;
  }

.center {
    display: block;
    margin-left: auto;
    margin-right: auto;
    width: 50%;
  }

  /* Three image containers (use 25% for four, and 50% for two, etc) */
.column {
    float: left;
    width: 50%;
    padding: 5px;
  }
  
  /* Clear floats after image containers */
  .row::after {
    content: "";
    clear: both;
    display: table;
  }

.centerDiv {
    display: block;
    margin-left: auto;
    margin-right: auto;
    width: 80%;
  }