シャニマス衣装コンペ
An official contest where fans were invited to design costumes for [[white day]]. The winner's outfits would later be implemented in the [[Idolmaster Shiny Colors]] browser game. The competition was held from September 29, 2023 to October 31, 2023. The winner was announced on December 22, 2023.

The contest was limited to Twitter, where fans could submit their designs by tagging them as "#シャニマス衣装コンペ":[https://twitter.com/hashtag/シャニマス衣装コンペ] (Shinymas Costume Competition) and "#ホワイトデー":[https://twitter.com/hashtag/ホワイトデー] (white day). The eligible units that could be chosen for the costumes were [[Illumination Stars (idolmaster)|]], [[L'Antica (idolmaster)|]], [[Noctchill (idolmaster)|]], and [[Shhis (idolmaster)|]].

More information can be found on the "official website":[https://idolmaster-official.jp/news/01_9490]
idolmaster shiny colors costume competition