CSS Code to display divs next to each other horizontally.

Inline

div {
  height:100px;
  width:100px;
  display: inline-block;
}

#red {
  background-color:#FF0000;
}

#blue {
  background-color:#0000FF;
}

#yellow {
  background-color:#E2BE22;
}

#green {
  background-color:#008800;
}