How to add more space above mainwrapper

First i want to say sorry if my first thread was added but after looking around and searching via search i coud not find it.

My problem is that i want to add some space above main wrapper. I thought it was easy but it didnt work for me. What i did is i inspected few site's who did it with firebugs and made the same change in my stylesheet.css

Looks like this now:

#mainWrapper {
background-color: #ffffff;
text-align: left;
width: 80%;
vertical-align: top;
border: 1px solid #9a9a9a;
margin-bottom: 25px;
margin-top: 25px;

the problem is i dont see any changed at live site.

Tnx in advance for ur help.

URL to your site would help

For some strange, counter-intuitive reason, if you want to move #mainWrapper down from the top of the page, you need to add margin-top to the body statement.