h2{
  text-align: center;
  border-bottom: solid 3px black;
  font-family: Georgia, serif;
}

#container{
  width: 800px;
  height: 800px;
}
.square {
    width: 400px;
    height: 400px;
    background-color: red;
    display: inline-block;
    float: left;
}
#squareBlue {
    background-color: blue;
}
#rectangleRed {
    width: 150px;
    height: 30px;
    background-color: red;
    display: inline-block;
}
#rectangleBlue{
  width: 150px;
  height: 30px;
  background-color: red;
  display: block;
}