body{
  background-color: whitesmoke;
  font-family: "Courier New", Courier, monospace;
  margin: 0px 100px 0px 100px;
}
footer{
  background-color: whitesmoke;
  font-family: "Courier New", Courier, monospace;
  text-align: center;
  margin: 0px 100px 0px 100px;
}
div {
  border-style: double;
}
* {
  box-sizing: border-box;
}
.column{
  flex: 50%;
  padding: 10px;
}
.row:after{
  display: flex;
}
.responsive{
  width: 100%;
  height: 100%;
}