Just the Docs has some specific configuration parameters that can be definied in your Jekyll site’s _config.yml file.

Search enabled

# Enable or disable the site search
search_enabled: true
# Aux links for the upper right navigation
    "Just the Docs on GitHub":
      - "//"

Color scheme

# Color scheme currently only supports "dark" or nil (default)
color_scheme: "dark"

See Customization for more information.