#topAd,#bottomAd {
  text-align:center;
  margin:10px auto;
}
.adslot_1{
  width: 320px; height: 100px;
}
.adslot_4{
  width:300px;
  height:250px;
}

/*///////////////////////////////*/
@media(min-width:500px){
 .adslot_1{
    width: 468px; height: 60px;
  }
.adslot_4{
  width:468px;
  height:60px;
}

}

/*///////////////////////////////*/
@media(min-width:768px){
  .adslot_1{
  width: 728px; height: 90px;
  }

.adslot_4{
  width:728px;
  height:90px;
}
}