Reproducible on: Nightly 38.0a1 (2015-02-22) Affected platforms: Windows 7 (x64), Windows 8.1 (x86) Steps to reproduce: 1. Launch Firefox with a clean profile. 2. Enable Reader Mode from about:config by setting 'reader.parse-on-load.enabled' to true. Restart the browser. 3. Set the Windows theme to high contrast - (e.g.) High Contrast #1. 4. Open an article from the web - (e.g.) http://www.bbc.com/news/world-australia-31579804 5. Enter Reader Mode by clicking the associated button from the Location Bar. 6. Set the Windows theme back to regular (non high contrast). 7. Exit Reader Mode either by clicking the close button from the controls sidebar or by clicking the button from the Location Bar. Expected result: Web pages displayed in Reader Mode as well as Reader Mode's UI itself are compatible with high contrast OS themes. Actual result: - The Reader Mode button from the Location Bar does not comply to high contrast themes. - Toggling Reader Mode while using a high-contrast theme has unexpected effects over the displayed web page. - The Reader Mode sidebar controls are invisible on high contrast themes. Notes: - This issue affects Windows only, the tests conducted on Ubuntu 14.04 (x64) showed positive results.

The white background on the urlbar icon is already covered by bug 1134658.