In an interview with Murase Aki (Kimi to Idol producer):
"I initially considered the idea of making Cure Idol's costume color Red Argyle (red checkered), but after her character design (in black and white) was completed and we tried coloring her costume in that color, the idea didn't work out and it didn't turn out to be a good idea. Ultimately, her main color was decided to be pink."
#precure