OFF toggle isn't showing properly for some color themes on IE11

Steps to reproduce:

1. Change color themes and observe the Watch List toggles

Objective

Fix the toggles display by using CSS. Make sure to test your change in Notifications area, in User Profile and other places toggles might be used. Test your changes with different browsers.

Expected Outcome

• Pull Request on the https://github.com/xwiki/xwiki-platform repository with the solution
• The summary of the Pull Request must have a first line matching the JIRA issue following by a colon and then the title of this issue
• Following best practices defined at http://dev.xwiki.org/xwiki/bin/view/Main/WebHome