Is there any pattern with secure (HTTPS) sites vs. regular (HTTP) sites?

For issues on secure sites:

• Check for a "shield" icon or gray exclamation triangle on the address bar and, if you find any notification icons, go ahead and click for more information.

• If you have had to make any exceptions for untrusted certificates, please check the "Issued by" section on one or two of the exceptions you've made to learn more about the source of this issue.

orange Firefox button (or Tools menu) > Options > Advanced > Certificates mini-tab > "View Certificates" button > Servers tab

Click a certificate and use the View button. The kind of issuer you might find is:

• Name associated with your security software, such as ESET, BitDefender, etc.
• Sendori (indicates unwanted software from Sendori)
• FiddlerRoot (indicates unwanted software named similarly to BrowserSafeguard, BrowserSafe, SafeGuard)
• Something else

I should have mentioned this first: When you have a problem with one particular site, a good "first thing to try" is clearing your Firefox cache and deleting your saved cookies for the site.

(1) Bypass Firefox's Cache

Use Ctrl+Shift+r to reload the page fresh from the server.

Alternately, you also can clear Firefox's cache completely using:

orange Firefox button (or Tools menu) > Options > Advanced

On the Network mini-tab > Cached Web Content : "Clear Now"

If you have a large hard drive, this might take a few minutes.

(2) Remove the site's cookies (save any pending work first). While viewing a page on the site:

• right-click and choose View Page Info > Security > "View Cookies"
• Alt+t (open the classic Tools menu) > Page Info > Security > "View Cookies"

In the dialog that opens, you can remove the site's cookies individually.

Then try reloading the page. Does that help?

I notice this pref in your System Details List:

• browser.display.use_system_colors: True

Make sure that you haven't enabled a High Contrast theme in the Windows/Mac Accessibility settings.

Make sure that you allow pages to choose their own colors.

• Tools > Options > Content : Fonts & Colors > Colors : [X] "Allow pages to choose their own colors, instead of my selections above"

Note that these settings affect background images.

See also:

• http://kb.mozillazine.org/Website_colors_are_wrong