.adslot_1 { 
width: 320px; 
height: 100px; 
}
.adslot_2 { 
width: 180px; 
height: 150px; 
}
@media (min-width:500px) { 
.adslot_1 { 
width: 468px; 
height: 60px; 
} 
.adslot_2 { 
width: 200px; 
height: 200px; 
}
}
@media (min-width:800px) { 
.adslot_1 { 
width: 728px; 
height: 90px; 
} 
.adslot_2 { 
width: 300px; 
height: 250px; 
}
}