Red: Red in ancient Chinese. The "red" mentioned by the ancients refers to pink and peach.

Qing: There are many meanings in ancient Chinese, one of which refers to sky blue, which is light blue.

Indigo: the color of vegetable dyes, dark blue. Because most ancient clothes were dyed with this dye, indigo is often used to represent deep blue.

It can be seen that all the above statements are correct, and the difference lies in the different meanings of ancient and modern times.