The indent is caused by one of your Template Monster stylesheets, stylesheet_boxes.css:
Code:
.box ul li {
border-bottom:1px solid #E9E9E9;
line-height:40px;
padding-left:18px;
}
To avoid changing your other sideboxes, add a new rule to your stylesheet_chcategories_dressing.css:
Code:
#chcategories ul li {/*category li containers*/ 
    margin: 0;
    padding: 0;
    }
I just tested this on your website and it works.