Define a custom subtitle for your book. This will appear below the title.

Provide a custom logo for your book.

Provide a completely custom header to your book. This will replace the whole area where usually the logo, title and subtitle appears.

Customize the background color of your book. Any valid value for the background CSS property will work.

Customize the background of your book using a gradient by providing the start and end color. This is just a helper since the same thing can be achieved by using the background attribute.

Customize the accent color of your book. This will change the color for a few different elements that sit on top of your background like the title and default logo.

Customize the nav background color of your book. This will affect both the background on hovered and active nav items as well as the background of the search field.

Customize the nav accent color of your book. This will affect the default text color for nav items.

Customize the nav accent highlight color of your book. This will affect the color of active nav items.

Makes your book always start as dark mode.

Add global elements to your book. This can be helpful for things like CSS resets.

For instance, if you're using elm-tailwind-modules, this would be really helpful:

import Css.Global exposing (global)
import Tailwind.Utilities exposing (globalStyles)


book "MyApp"
    |> withStatefulOptions [
        globals [ global globalStyles ]
    ]