Screenshot of unreadable maths on high contrast theme.
When using a high contrast theme on Windows 7 (and maybe other OSs/versions), designed for visually impaired users, the output from "<math>" tags is almost unreadable. This is on Firefox with "Menu->Tools->Options->Content->Fonts & Colours->Advanced->Allow pages to choose their own colours" disabled (and the same under the "Colours" button above the "Advanced" button, instead opting to use the default OS theme.
The theme in the OS is "High Contrast #1" - a default theme with yellow writing on a black background for better reading. The issue seems to come from the PNGs used to render the maths formulas having transparency and assuming that the background is always white. Attached is a screenshot of how these appear. This seems more serious than normal issues with custom themes given that it is a default theme designed to improve accessibility and instead restricts it.
OS: Windows 7