In familiarizing myself with Windows 10, I tried the "High Contrast" setting. After perusing the various options, I reverted to the normal Windows setting that I previously had, but Mozilla Firefox remained in a high contrast setting that was substantially less appealing than the prior default setting. So, after successfully turning off high contrast in Windows several times, I became a bit consternated to find that Firefox was still in that unwanted mode.
The solution: Firefox Tools/ Options/ General/ Language and Appearance/ Content: Fonts and Colors: > colors/ "Override the colors specified by the page with my selections above" > select "never" and you are back to normal. Just in case anyone has tried high contrast and left it and found that Firefox still appeared as such instead of its normal mode. The "never" setting had been changed to "always", and that was the cause of the problem
