Repeat Pattern to 100% of the viewport

in CSS i made that code:

   body {
    background-color:#f3f3f3;
    max-width:1920px;
    min-width:1024px;
    margin:0 auto;

but to seperate the header from the content i would like to have a "bar" between them.

so i made:

#zig {
max-width:100%;
background-image:url(../img/zig.png);
background-repeat:repeat-x;
height:25px;

but the Bar doesn't go "unlimited" it just repeat till it reaches "1920px" can i somehow change that? to put

min-width:100%

didn't work