Problem in Active Menu....

Hello.
I have a problem with the active menu. Please see image attached.

The CSS:

div#maximenuCK ul.maximenuCK li.item125.current> a {
background-image: url(../images/mainnav-blue.gif);
background-position: left top;
background-repeat: repeat-x;
margin: 0;
}

Background does not take the width of the menu seems to have padding, how I can adjust?

thanks

hi
use firebug to indentify the css
CEd