The Wire color palette consists of a neutral gray and seven vivid colors. The colors have been chosen based on the accent colors from the Wire apps and you can combine them freely with one another. A good rule of thumb is to focus on a single color and complement it with black or white as you see fit.
Sometimes the colors need an exception. It’s fine to derive variations of Wire colors by using simple math to lighten or darken them gradually. There’s no specific formula, but remember — the simpler the logic, the easier the result.