media query iDevice not working

If media queries on iPhone or iPad not working you have to "enable" it in html.

<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=yes user-scalable=no">

/* iPad portait */
@media (max-width: 768px) {
body {
font-size: 3vmin;
}
}

/* iPhone landscape only */
@media (max-width: 568px) {
body {
font-size: 4vmin;
}
}

/* iPhone portait only */
@media (max-width: 320px) {
body {
font-size: 4vmin;
}
}