Web and WebWorks Development

[Ohope5]

I am writing an app for BB OS 6/7 and am not sure how I should write the CSS. I originally wrote it all using % sizing which I quickly discovered simply does not work. Now I have re-written it using px. However, I am stuck as I know that different Blackberry phones have different screen sizes. What should I do about this? Write multiple CSS files?
I would be grateful for any help. Thank You in advance.

[TheFlowFX]

Have you tried using this?

<meta id="viewport" name="viewport" content="initial-scale=1.0, width=device-width, user-scalable=no, target-densitydpi=device-dpi" />

[Ohope5]

Do you mean to use with the % or px?

[TheFlowFX · Accepted solution]

That code should be between your head tags. If your going to use css for certain classes, you shouldnt have to use px or %. 

Have a look at this:

Device width

[Ohope5]

Oh right, I understand now. Thanks, I'm completely new to this, so that was a great help.