Getting Media Queries To Work

I'm using WordPress for our intranet and incorporating the Less Framework template so our pages respond to the device. I learned that I need to add the following line to the header.php file. I added it after the stylesheet call.

<meta name="viewport" content="width=device-width, 
initial-scale=1"/>

Also, I changed the tablet dimensions to the following:

@media only screen and (min-width: 768px) and (max-width: 1024px) { }