CSS media query tests

Dimensions

Min-width: 320px only screen and (min-width: 320px)
Min-width: 480px only screen and (min-width: 480px)
Min-width: 768px only screen and (min-width: 768px)
Min-width: 1024px only screen and (min-width: 1024px)
Min-width: 1024px (tablet) only screen and (min-width: 1024px), only screen and (min-device-height: 1024px) and (orientation: landscape)

From http://css-tricks.com/snippets/css/media-queries-for-standard-devices/.

Smartphones (portrait and landscape) only screen and (min-device-width : 320px) and (max-device-width : 480px)
Smartphones (landscape) only screen and (min-width : 321px)
Smartphones (portrait) only screen and (max-width : 320px)
iPads (portrait and landscape) only screen and (min-device-width : 768px) and (max-device-width : 1024px)
iPads (landscape) only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : landscape)
iPads (portrait) only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : portrait)
Desktops and laptops only screen and (min-width : 1224px)
Large screens only screen and (min-width : 1824px)
iPhone 4 only screen and (-webkit-min-device-pixel-ratio : 1.5), only screen and (min-device-pixel-ratio : 1.5)