Residential development, up to 30 units per acre, including: (a) residences occupying second floors (e.g., above ground floor nonresidential uses) including single-room occupancies, boardinghouses, apartments, and stacked-flat style condominiums; and (b) attached two- and three-story residences occupying their own site. This second form of residential use is limited to townhouse-style condominiums, townhouse-style zero lot line single-family dwellings in a townhouse configuration. No ground level units are permitted north of Seventh Street on Guadalupe Street, consistent with the General Plan land use designation of Downtown Mixed-Use, and following the development standards of the design review provisions;