In reality, this is related to the hekketsu event (see 'hekketsu-hi'), and the clothing worn as well as the covers laid on the floor were pale yellow (pale yellow + red = green).
実際には碧血の故事（碧血碑を参照のこと）にちなみ、着る物や敷く物は浅黄色に整えられた（浅黄色+赤=碧色）。