Changing margin between menu items

How do I change the space between menu items. My menu only has images. I want them closer. How do I change the width of each menu item?

Try to remove 4px padding as follows:

div.dhtmlxMenu_dhx_skyblue_TopLevel_Item_Normal, div.dhtmlxMenu_dhx_skyblue_TopLevel_Item_Disabled, div.dhtmlxMenu_dhx_skyblue_TopLevel_Item_Selected {

That removed the gap. Thanks.