Сложности в использовании @media

@media screen and (min-device-height: 849px) and (max-device-height: 899px) { 
    body footer #relativefooter { 
        bottom: 51px 
    } 
     
    body footer .end { 
        bottom: 51px 
    } 
} 
  
@media screen and (min-device-height: 799px) and (max-device-height: 848px) { 
    body footer #relativefooter { 
        bottom: 101px 
    } 
     
    body footer .end { 
        bottom: 101px 
    } 
} 
  
@media screen and (min-device-height: 767px) and (max-device-height: 799px) { 
    body footer #relativefooter { 
        bottom: 133px 
    } 
     
    body footer .end { 
        bottom: 133px 
    } 
} 
  
@media screen and (min-device-height: 600px) and (max-device-height: 766px) { 
    body footer #relativefooter { 
        bottom: 300px 
    } 
     
    body footer .end { 
        bottom: 300px 
    }