You may find the text of the Monero wallet to be hard to read on a white background. You can change your terminal to have a black background by pressing Edit in the menu bar -> Profile Preferences -> Colors, then uncheck 'Use colors from system theme'.
These settings will not persist after a reboot.
To persist this setting after a reboot:
1 Enable dotfiles persistence
2 Restart Tails
3 Open a terminal
4 Change the terminal colors according to your preferences
5 In the terminal type:
mkdir -p /live/persistence/TailsData_unlocked/dotfiles/.config/dconf
cp ~/.config/dconf/user /live/persistence/TailsData_unlocked/dotfiles/.config/dconf
6 Restart Tails