h1{ text-align: center; }

#canvas{
  
  position: relative;
  width: 80vmin;
  height: 80vmin;
  background-color: #556;
  margin: 0 auto;
}
#col2{
  left: 27vmin;
  position: absolute;
  background-color: rgb(144,50,40);
  width: 27vmin;
  height: 80vmin;
  }
#col3{
  top:0;
  left: 53vmin;
  position: absolute;
  background-color: goldenrod;
  width: 27vmin;
  height: 80vmin}