Atom Babel plugin doesn’t highlight variables in ES6 (ES2015) template strings.

You’ll need to add this snippet to your Atom’s style.less

atom-text-editor::shadow .variable.js { color: #F8F8F2; } 

In general, you can just inspect stuff in Atom, find out what classes element are using, and then style it via CSS (LESS). Just don’t forget to add atom-text-editor::shadow before your rules.

If anyone is interested, I’m using Monokai Seti theme.