For every segment you can specify foreground and background color by setting them in your `~/.zshrc`:
POWERLEVEL9K_TIME_FOREGROUND='red'
POWERLEVEL9K_TIME_BACKGROUND='blue'
This will change the appearance of the `time` segment. Take the segment names from the Chapter `Segment Customization`.
Some of the Segments have special color variables, as they change the colors according some internal rules. These Segments are `vcs`, `rspec_stats`, `symfony2_tests`: