Logo Area Background (Above User 3)

The logo area above User 3 and to the left of user 4 (user 4 sits within this space) has a gradient background when you choose a color in the custom style area. I'd like to turn that off, or remove the gradient. Could you point me to the right place to change this please.

Link to the site is absoluteballroom.crmconcept.net

layout.css:

.header {
height: 100px;
margin: 0 auto;
background: url(../images/header_bg.png) repeat-x;
}

remove background property.

Excellent! That worked perfectly. Thank you for your prompt response.