How to add a woothemes like notification bar?

I would like to add a fixed notification bar (like the yellow one here) on my website: http://balloonup.com. I tried to put the followings just after the body:

<div id="notification-wrapper"
style="border-bottom: 1px solid #C69A00;
background-color: #FEF28F;top:0;
position: fixed;z-ind开发者_运维问答ex: 99999;width: 100%;">
<em>Hello world!</em>
</div>

Unfortunately, this yellow bar overlaps my header.

Any idea?

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In woothemes example they've just pushed down the first content box (#top) through margin-top with the height of the "notification bar" just like @rockinthesixstring wrote.