.adfloat {
  display: block;
  float: right;
  margin: 5px;
}

.ad-300x250,
.ad-300x600,
.ad-728x90 {
  display: inline-block;
}

.ad-300x250 {
  width: 300px;
  height: 250px;
}

.ad-300x600 {
  width: 300px;
  height: 600px;
}

.ad-728x90 {
  width: 728px;
  height: 90px;
}