Change Header Depending to Screen Size

[keyness]

Hello,

I designed a header for 1280 and above screen width. But when screen width is below than 1280 pixels, it doesn't look well. So I want to change header depending to user's screen width.

I tried something like that in header template, but it didn't work:

<vb:if condition="screen.width <= '1280'">

Header code for above 1280px

</else>

Header code for below 1280px

</vb:if>

Where I am mistaken?