Once Opera’s guys proposed to use @viewport { ... } in CSS instead of <meta name="viewport" ...> tag. Regarding the reasons you’d better watch and listen to @ppk and I will explain why you should use this right now.

I’ve noticed long ago that websites on Windows Phone look bulky in landscape mode but never deeply thought about the fact.

You might overlook the difference between iOS and Windows Phone views in portrait mode:

Windows Phone 8.1 iOS 7

However in the landscape mode the enourmousness of Windows Phone view becomes clear:





Windows Phone 8.1





iOS 7

It turned out that Windows Phone considers usual <meta name="viewport" content="width=device-width, initial-scale=1"> as a designation to make a viewport 320 logical pixels wide, no matter what real device resolution is (because iPhone).

Instead, fresh and lush @viewport {width: device-width;} currently being supported by IE10 and IE11 with prefix overrides this meta’s value; and moreover – instructs a Windows Phone to use its native viewport resolution.

This is how it should work:





Before





After

The portrait mode also undergoes a change. HTC 8x has better resolution then iPod and same pixel density, so its viewport should be a little bit wider than 320 pixels:

Before After

@-ms-viewport was buggy in WP 8 before its third update because it operated with real pixels and not with logical ones. This caused too large viewport size (and so too small website view) in the retinish phones.

Third update came out a while ago, older phones running WP7 are not affected by the bug, so now this bug can be safely ignored.

Besides, as it proved, IE in Windows 8 ignores the meta tag in metro mode but correctly interprets @-ms-viewport . Here there are a couple of explanatory GIFs:





The web site is zoomed when using meta tag.





The website adapts when using @-ms-viwport .

In the first case we get a non-adaptive web site. Bad. The second approach gives a mobile version snapped to the edge of the screen. Splendid!

All the real guys are now combining the meta tag:

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

with CSS @viewport declaration:

@-ms-viewport { width: device-width; } @viewport { width: device-width; }

Advantages:

Responsiveness in IE on Windows 8

Native viewport in IE on Windows Phones

Future-proof!

Drawbacks: