Dimming screen in IBooks

Is there a mechanism for dimming the font when reading on the iBooks app? Apple seems to have done a redesign of iBooks and you can no longer dim the font/letters on the page (or I can't figure out how). I realize that I am able to adjust the background to black, light, etc. but the letters on the page are so incredibly bright, particularly in the darker background fonts. You used to be able to dim the entire page so that it was not so intense, particularly when you are trying to read at night and wind down.

the app changed, and the loss of this feature is significant. I know how to choose the setting the theme settings, and the dark mode, but we’ve lost the ability to customize the brightness of the font on the page.