Door and window openings. For existing structures, windows must fit existing openings with no exception. If the building has already been altered to change existing openings, windows must fit the original openings that existed prior to the alteration. For new commercial, mixed-use or civic buildings, windows and doors or openings shall comprise at least 50% of the length and at least 40% of the area of the ground-floor primary street facade. Glass on windows and doors shall be clear, allowing views into and out of the interior. For windows in areas that are not shaded, use either blue or green tinted glass with maximum transparency (minimum visible transmittance rating of 0.70).