How to apply class to banner?

https://www.superiorsoundco.com/wordpress/

If you look, the banner on my site is all the way to the left. I tried applying the class below to it and it doesn’t work?

<div class=”banner”><img src=”<?php bloginfo(‘template_url’); ?>/images/banner.png” width=”700px” class=”banner” alt=”banner” ></div><! –/banner –>

Here’s the class:

#banner {
margin: 5px 0px 0px 115px;
}