#header-wrapper{
margin:0 auto 0;
padding:2% 0;
background-color:#66666;
background-image:-webkit-linear-gradient(#4E4E4E,#2E2E2E);
background-image:-moz-linear-gradient(#4E4E4E,#2E2E2E);
background-image:-o-linear-gradient(#4E4E4E,#2E2E2E);
background-image:-ms-linear-gradient(#4E4E4E,#2E2E2E);
background-image:linear-gradient(#4E4E4E,#2E2E2E);
color:white;
width:98%;
border-color:white;
border-style:solid;
border-width:0 1px;
overflow:hidden
}

Kodun genişletilmiş hali bu şekilde. Bu koddaki background-image kodlarını silersen istediğin arkaplan rengini yapabilirsin.