Here is Kagi's quick answer [0], where its AI "extracts and summarizes the important content from the search results including links to the source material":
"Kagi supports dark mode functionality to reduce eye strain.[1][2] Users can select between the Royal Blue or Moon Dark default themes in their appearance settings. Additionally, the Orion browser powered by Kagi includes dark mode that can be toggled on websites.[3]"
When I logged in with my Google account, it detected the system setting.