Atom: highlight git changed/modified lines in the gutter background

gutter.png

styles.less

// show highlights for changed/modified diff lines in the gutter
@import "syntax-variables";
atom-text-editor,
atom-text-editor::shadow {
  .gutter .line-number {
      &.git-line-modified {
        background-color: fade( @syntax-color-modified, 20% );
      }

      &.git-line-added {
        background-color: fade( @syntax-color-added, 20% );
      }

  }
}