nebular: Error in production build

Issue type

I’m submitting a … (check one with “x”)

• [ x] bug report
• feature request

Issue description

I’m using v2.0.0-rc.10. The production build is producing the following error: Current behavior:

[ERROR] Error: Parse error on line 1:                                                                                                                                   
[ERROR] (* 1.25) + 4px  

Expected behavior:

Steps to reproduce:

Related code:

insert short code snippets here

Other information:

npm, node, OS, Browser

npm: v6.4.1
node: v8.12.0
OS: Windows 10
Browser: Chrome

Angular, Nebular

Angular : 6.1.0
Nebular: v2.0.0-rc.10