Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:57.0) Gecko/20100101 Firefox/57.0 Build ID: 20170912013600 [Affected versions]: Nightly 57.0a1 [Affected platforms]: Tested on Mac OSX 10.12 [Steps to reproduce]: 1.Launch Nightly 57.0a1 with a new profile. 2. Open several new tabs. [Expected result]: All Firefox default theme colors respect the specifications provided. [Actual result]: Some of Firefox default theme colors do not respect the specifications. [Notes]: For more details please check the attached screenshot.

I verify on Windows 8.1 x64 and its also reproducible. Please take a look on the attachment.

On windows 7 with the default theme, the color codes are not respected, see the attachment with the expected and with red color are the actual results.

Win 7 - Light Theme, see the attachment with the expected and with the actual results (where the color doesn't match the spec. we put the actual result)

Windows 7 dark theme colors don't match the spec.

This is reproducible on Windows 10, with latest Nightly 57.0a1 build ID 20170913220121 as follows: Default Theme colors: E should be #0C0C0D, but the actual color is #000000 F should be #0A84FF, but the actual color is #3399FF Light Theme colors: E should be #0C0C0D, but the actual color is #18191A F should be #0A84FF, but the actual color is #3399FF C should be #DFDFDB, but the actual color is #E3E4E6 B should be #F9F9FA, but the actual color is #F5F6F7 Dark Theme colors: F should be #0A84FF, but the actual color is #3399FF D should be #4A4A4F, but the actual color is #323234

i verify this issue on windows 10 x64 and it's also reproducible

Reproducible on Windows 7 with Basic Theme and Firefox 57 beta 12: Default Theme: B should be #F9F9FA - correct on text and toolbar, wrong on border (##654E4C) and "+" sign (#F4EEEA) E should be #0C0C0D, but the actual color is #000000 on text and #4B4B4B on toolbar icons Light Theme: B should be #F9F9FA, but the actual color varies C should be #D7D7DB, but the actual color is #C9D7E5 E on text should be #0C0C0D, but the actual color is #18191A E on border should be #0C0C0D, but the actual color is #BBBBBD E on icons should be #0C0C0D, but the actual color is #5B5B5D E on "+" should be #0C0C0D, but the actual color is #EAEFF4 Dark Theme: B on border should be #F9F9FA, but the actual color is #3C3C3C B on "+" should be #F9F9FA, but the actual color is #EAEFF4 B on icons should be #F9F9FA, but the actual color is #BDBDBF D should be #4A4A4F, but the actual color is #323234 E should be #0C0C0D, but the actual color varies and is not dark