Literature Reference: 朱颜白日相隳颓。—— 《相和歌辞 短歌行二首 一》 白居易 The rosy cheeks and bright days gradually decline. Source from 'Xianghe Geci: Short Song Lines Part 1' by Bai Juyi.
朱: Vermilion, a deep red hue; the name of a mineral; an ancient geographical location; and a surname.
颜: Visage, countenance.
Meaning: Rosy cheeks symbolize youth and beauty.