1 John 1:5 says God is what, and in Him there is no darkness at all?

Answer: Light

John's message is that God is light, and in Him there is no darkness at all; so those who walk in darkness cannot claim fellowship with Him.

“And this is the message we have heard from Him and announce to you: God is light, and in Him there is no darkness at all.”— 1 John 1:5 (BSB)