CSS3 Media Queries

/* Smartphones (portrait and landscape) ----------- */@media only screenand (min-device-width : 320px)and (max-device-width : 480px) {/* Styles */}

/* Smartphones (landscape) ----------- */@media only screenand (min-width : 321px) {/* Styles */}

/* Smartphones (portrait) ----------- */@media only screenand (max-width : 320px) {/* Styles */}

/* iPads (portrait and landscape) ----------- */@media only screenand (min-device-width : 768px)and (max-device-width : 1024px) {/* Styles */}

/* iPads (landscape) ----------- */@media only screenand (min-device-width : 768px)and (max-device-width : 1024px)and (orientation : landscape) {/* Styles */}

/* iPads (portrait) ----------- */@media only screenand (min-device-width : 768px)and (max-device-width : 1024px)and (orientation : portrait) {/* Styles */}

/* Desktops and laptops ----------- */@media only screenand (min-width : 1224px) {/* Styles */}

/* Large screens ----------- */@media only screenand (min-width : 1824px) {/* Styles */}

/* iPhone 4 ----------- */@mediaonly screen and (-webkit-min-device-pixel-ratio : 1.5),only screen and (min-device-pixel-ratio : 1.5) {/* Styles */}
<head>

<link rel=stylesheet href=smartphone.cssmedia='only screen and (min-device-width : 320px)and (max-device-width : 480px)'>

<link rel=stylesheet href=smartphone-landscape.cssmedia='only screen and (min-width : 321px)'>

<link rel=stylesheet href=smartphone-portrait.cssmedia='only screen and (max-width : 320px)'>

<link rel=stylesheet href=ipad.cssmedia='only screenand (min-device-width : 768px)and (max-device-width : 1024px)'>

<link rel=stylesheet href=ipad-landscape.cssmedia='only screenand (min-device-width : 768px)and (max-device-width : 1024px)and (orientation : landscape)'>

<link rel=stylesheet href=ipad-portrait.cssmedia='only screenand (min-device-width : 768px)and (max-device-width : 1024px)and (orientation : portrait)'>

<link rel=stylesheet href=widescreen.cssmedia='only screen and (min-width : 1824px)'>

<link rel=stylesheet href=iphone4.cssmedia='only screenand (-webkit-min-device-pixel-ratio : 1.5),only screen and (min-device-pixel-ratio : 1.5)'>

</head>