This is an adaption of Spacemacs theme for Atom. The original theme is a wonderful work nashamri/spacemacs-theme.
With Atom Material UI.
You can get closer to the original atmosphere by setting primary color as #5d4d7a for Dark theme, and #d3d3e7 for Light theme.
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.