Atom UI theme with vibrancy support. Vibrancy it's kinda buggy and only available on macOS. You can use a background image to imitate the effect on unsupported platforms (Windows and GNU/Linux).
Based on Simurai's starter template.
Fire up a Terminal and type:
apm install vibrance-ui
Or… within Atom's settings. After that, you'll be able to pick the theme from Atom's settings.
I've only got one computer, a 2015 MacBook running macOS High Sierra
10.13.6, and vibrancy it's buggy AF. It's not a theme issue, it's Electron.
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.