Medium-to-high contrast theme, hinting towards the blue side of the spectrum. Its most prevalent colours are variants of violet, green, blue, cyan, and orange.
Caprice is available in separate light and dark themes (see further info below).
caprice-syntax in Settings > Install > Themes. Or install it directly using the command:
apm install caprice-syntax
Project page: https://protesilaos.com/caprice
Caprice dark version: https://atom.io/themes/caprice-dark-syntax
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.