xxxxxxxxxx
@media (min-width: 640px) { }
@media (min-width: 768px) { }
@media (min-width: 1024px) { }
@media (min-width: 1280px) { }
@media (min-width: 1536px) { }
xxxxxxxxxx
@media (min-width: 600px) and (max-width: 800px) {
/* your css code here */
/* html { background: red; } */
}