She wears both red and blue, as does Her Son, OLGS Jesus Christ.
Our Lord is often presented in icons with a red tunic with a blue robe that is wrapped around Him. This signifies, theologically, that the Divine Word "wrapped" Himself in Flesh from the Most Holy Virgin Mary. Blue is the colour of our humanity i.e. since blood flowing through our veins is blue.
The colour pattern is the opposite for the Mother of God to signify her Theosis and great dignity being "wrapped" in the Divine Holy Spirit.
Most Holy Theotokos save us!
I've seen many old images of the Theotokos, God-bearer, wearing red inner garment and a blue mantle...
In addition to red meaning divine and blue meaning earthly/human, didn't virgins wear red garments and mothers blue?...By this notion, Our Holy Theotokos, as Virgin Mother, wrapped her virginity with motherhood...divine with earthly...
Doesn't dark blue in Byzantine art also symbolize royalty/empress, as Mary is the Queen of Heaven?
Such a beautiful mystery!
Theotokos, comfort us and bring us close to your bosom, under your protective mantle, as you did to Our Lord, when He was a little child...