trigger

The default style for a trigger is to look like a button:

xf\:trigger
{
    padding          : 0 0 0 0;
    margin-right     : 10px;
    border-top       : 2px outset #e0e0e0;
    border-right     : 2px outset #191919;
    border-bottom    : 2px outset #191919;
    border-left      : 2px outset #e0e0e0;
    background-color : #d0d0d0;
}

xf\:trigger xf\:label
{
    display          : inline-block;
    padding-top	     : 3px;
    padding-left     : 5px;
    padding-bottom   : 3px;
    padding-right    : 5px;
    margin           : 0 0 0 0;
    border           : none;
    background-color : #d0d0d0;
    width            : auto;
    font-family	     : arial;
    cursor           : pointer;
}