html {
    font-size:62.5%
}
  
@media only screen and (min-width: 1800px) {
    html{
        font-size: 75%;
    }
}	

@media only screen and (max-width: 1580px) {
    html{
        font-size: 58%;
    }
}

@media only screen and (max-width: 1470px) {
    html{
        font-size: 55%;
    }
}

@media only screen and (max-width: 1395px) {
    html{
        font-size: 50%;
    }
}

@media only screen and (max-width: 767px) {
    html{
        font-size: 50%;
    }
}