CSS Media Queries Issue

CSS media queries seem to be firing too soon. I have one set at 1600px which is firing at 1760px.

Some of my CSS here...

.main-header {
min-height: 100vh;
padding: 0 15rem;
}

@media (max-width: 1600px) {
.main-header {
padding: 0 4rem;
}
}

~~~