Abstract We report on multicolor photometry of the short-period dwarf nova CSS130418:174033+414756 during the 2013 superoutburst. The system showed an unusually short superhump period of 0.046346(67) d during stage A, which is one of the shortest periods among dwarf novae below the period minimum. We found that the bluest peaks in g΄ − Ic color variations tended to coincide with the brightness minima of the superhump modulations. We also studied nightly-averaged superhump amplitudes in the g΄, Rc, and Ic bands and found that they have less dependence on wavelength. These properties are likely to be in common with dwarf novae exhibiting superhumps. We successfully obtained g΄ − Rc and Rc − Ic colors during the temporal dip. The color indices were significantly bluer compared with other dips of WZ Sge-type dwarf novae. By using the period of the growing superhumps, we estimated the mass ratio to be q = 0.077(5), which is much larger than the previous study.