The Cardano logo is presented as a dark grey or black mono logo. Although there are no official brand guidelines, the most commonly used colours are listed here. The Cardano Foundation logo uses black and a shade of blue.

Cardano Logo

#333333
Cardano Grey
Hex: #333333
RGB: 51, 51, 51

#2a71d0
Cardano Foundation Blue
Hex: #2a71d0
RGB: 42, 113, 208

#000000
Cardano Foundation Black
Hex: #000000
RGB: 0, 0, 0