Themes: menu bar background image, 2010Weaver

Any tips on placing a background image in the menu bar in 2010weaver? I’ve set the color as “transparent’ in the theme options – that works fine for removing color- but I’m stuck on how to get a single skinny image to span the width of the menu bar, behind the links. The image is 940x40px.
Using this css in the style sheet, also tried it in the 2010Style.css:
#access {
background-image: url(“https://stevesnelling.com/images/menubacks/Nighthawks.png”) center center no-repeat;
display: block;
float: left;
margin: 0 auto;
width: 940px;
}
Here’s the site url: https://www.stevesnelling.com