A “day” is the period of time between any midnight and midnight following. The time in which any act provided by this chapter is to be performed is computed by excluding the first day and including the last, unless the last day is a holiday, and then it is also excluded. If City offices are closed for the whole of any day, that day shall be considered a holiday. When this chapter prescribes filing deadlines, all acts necessary to complete filing must be completed no later than 5:00 p.m. of the last day or such earlier time as City offices may officially close for the day.