Look into KOReader for the Kobo, its a little involved to first install, but once you get used to the install process n stuff, KOReader is awesome! It supports a "dark mode" where it just inverts the colors and you can also turn on SSH and then use that to transfer books over WiFi. Just remember to turn off SSH when you're done and don't use SSH on a public network! SSH is easy to setup with root and password less login