Momoiro Clover Z Fashion?

I don't understand why these clothes are so popular, but it has something to do with a J-Pop band called Momoiro Clover Z. Seems that there are several variations of colors and hoody styles. The text on the sashes lead me to the name of the band. According to Wikipedia, it seems that they ranked as the most popular female idol group according to 2013 and 2014 surveys.

Based on my investigative work, it seems that there was some sort of event or concert planned at Meiji Jingu Gaien Stadium.

Nikon D600 with Nikon 16-35mm f/4G ED VR II AF-S IF SWM @ 16 mm, f5.6, ISO 100, 1/80 sec.

Nikon D600 with Nikon 16-35mm f/4G ED VR II AF-S IF SWM @ 16 mm, f5.6, ISO 100, 1/250 sec.

Nikon D600 with Nikon 16-35mm f/4G ED VR II AF-S IF SWM @ 35 mm, f5.6, ISO 100, 1/160 sec.

Nikon D600 with Nikon 16-35mm f/4G ED VR II AF-S IF SWM @ 35 mm, f5.6, ISO 100, 1/80 sec.

Nikon D600 with Nikon 16-35mm f/4G ED VR II AF-S IF SWM @ 35 mm, f5.6, ISO 100, 1/320 sec.