When check it in Opera Mobile Emulator and on devices, it appears, that styles for wvgaPort apply only at 599px, then for 800 - at 1200, for 1024 at 1533. Why does it happen? And what is a better why to define these media rules?
/* Media */
$wvgaPort: 400px
$wvgaLand: 800px
$wsvgaPort: 600px
$wsvgaLand: 1024px
$desktop: 1280px
=apply-to($media)
@if $media == smartPort
@media only screen and (min-device-width: $wvgaPort) and (max-device-width: $wsvgaPort) and (orientation: portrait)
@content
@else if $media == smartLand
@media only screen and (min-device-width: $wvgaLand) and (max-device-width: $wsvgaLand) and (orientation: landscape)
@content
@else if $media == tabPort
@media only screen and (min-device-width: $wsvgaPort + 1) and (max-device-width: $desktop) and (orientation: portrait)
@content
@else if $media == tabLand
@media only screen and (min-device-width: $wsvgaLand + 1) and (max-device-width: $desktop) and (orientation: landscape)
@content
html, body
+apply-to(smartPort)
font-size: 87.5% !important
#header
+apply-to(smartPort)
background: red
color: #000
+apply-to(smartLand)
background: blue