@media (min-width: 768px) and (max-width: 991px) { html{ color: black; } }
@media screen and (min-width: 768px) { html{ color: red; } }
@media all    and    (min-width: 50px)   and    (max-width: 100px)   { html{ color: green; } }
@media screen { html{ color: gray; } }