One sign in connection with a permitted or lawful nonconforming use, provided that such sign shall pertain to and be located on the site of the principal use. Such signs shall be no greater than 12 square feet in area and shall be located no closer than 30 feet to any R District. Such signs shall project no more than 5 feet above the main cornice line of the structure to which they pertain. Signs shall be located no closer than 5 feet to a front lot line except where they are attached to a structure housing the principal use. In such cases, no part of any sign shall project over a public right-of-way and no portion of any projecting sign shall be less than 10 feet above the grade of the land below. Signs shall be illuminated only by continuous, white, indirect lighting with no animation or movement.