@media screen and (max-width: 5000px) {

.main {
float:left; 
width:47%
}

.right {
float:right;
width:24%;
}

.left {
float:left; 
width:29%;
}

}

@media screen and (max-width: 1350px) {

.main {
float:left; 
width:71%
}

.right {
display: none;
}

.left {
float:left; 
width:29%;
}

}
@media screen and (max-width: 1199px) {

.main {
float:left; 
width:100%;
}

.right {
display: none;
}

.left {
display: none;
}

}