New jailbreak tweak called BlackKeyboardEverywhere applies a dark theme to stock iOS 10 keyboard. Normally the stock keyboard in iOS 10 has a white theme, but if you launch Spotlight Search from your Home screen, the keyboard will will become dark with translucent background. If you better prefer the second variant then BlackKeyboardEverywhere jailbreak tweak will turn your stock iOS keyboard into a dark keyboard.
How To Apply A Dark Theme To Stock iOS 10 Keyboard
BlackKeyboardEverywhere tweak applies the Spotlight keyboard style to your stock keyboard. It means that once this tweak is installed instead of the white keyboard, you will see a dark keyboard with a semi-transparent background, just like how it appears in Spotlight Search.
The big advantage is that once you install the tweak the dark keyboard will appear everywhere across your device. It will work with third-party apps, system apps and anywhere that the keyboard appears. So to apply a dark theme to stock iOS 10 keyboard on your jailbroken device you’ll have to add the following source to Cydia: rishanan.github.io . Once done Cydia will refresh and you should be able to find the tweak in the Changes tab. Note the tweak works with both iOS 9 and iOS 10.
BlackKeyboard tweak doesn’t have any options for configuration, but if you prefer to have a black background rather than a semi-transparent one, it is possible to change it. All you have to do is to navigate to Settings -> General -> Acessibility -> Increase Contrast and toggle off Reduce Transparency. This will change the background of the keyboard to black. This option will also apply to other iOS elements that have a transparent background such as the Home screen dock, so keep this in mind.
So if you prefer a dark color of your iOS 10 keyboard then you can easily enable it with BlackKeyboardEverywhere tweak that is totally free.