Forum display?

Something that has been niggling me for some time.
I use a few different computers for internet surfing, all with firefox.
My main computer, which I use most of the time, with my best and biggest monitor just displays all the forum pages and posts with a white background and blue text.

On this different computer and others, alternative threads are dislayed with different colour backgrounds, either in white or very pale blue.
Also when a post includes a quote from another post, that quote is displayed in white with the new post in pale blue.
see attachments

What do other people see?
Is it something to do with the monitor or computer colour setting or
some setting in firefox, or even some forum setting?
I prefer the slightly different colours to just having white.

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Edit
I've just logged into my main computer and the screenshot attachments I posted from the other computer also look white to me now.
That eliminates some forum (user CP) setting anyway.

Certainly when I am reading posts within posts the original is white and the new one pale blue which makes it hard to tell the difference! Surely this could be changed by someone very clever? (Certainly not me lol!!!!). I would prefer more vivid colour differences.

I see different colours that are clearly different.

I think it's down to both Monitor & Display settings of your graphics card.

I too use Firefox, and although the colour shading can be seen, it's not pronounced on mine. It's just a very pale egg-shell blue to me.

Plus it seems to alternate for me on the pages, one line with white background, the next with egg-shell blue.

The more pronounced views, are more likely due to the contrast setting on the monitor, rather than the graphics card settings.

I see different colours and whether I use Firefox or Internet Exporer makes no difference, the colours are still different, so I doubt that it's a browser setting. Just to check I loaded Safari as I have that browser on my computer too and the colours are still different.

I copied a screenshot of it made with my other computer, where the 2 colour background can be seen, onto this computer.
On this one, the background in the screenshot is all white when viewed with the image viewer, so its obviously nothing to do with firefox or the website. Its something to do with the general colour settings on this computer or monitor.