body {
  background-color: #C287FF;
}

.header {
  margin: 50px;
}

.column {
  float: left;
  box-sizing: border-box;
}

.column.middle {
  background-color: white;
  width: 60%;
  height: 600px;
  padding: 10px;
  border-style: double;
  border-width: 5px;
  border-color: white;
  border-radius: 10px;
}

.column.side {
  width: 20%;
  padding: 20px;
}

.row::after {
  content: "";
  display: table;
  clear: both;
}