prefers-color-scheme: dark, not functioning as expected

Number:rdar://50578827 Date Originated:
Status:Open Resolved:
Product:Mail Product Version:12.4 (3445.104.8)
Classification:Bug Reproducible:yes
When an HTML email is read using dark mode, the colours are edited to be inverted. This can cause accessibility issues and dramatic inconsistencies between the Apple Mail app and other email clients or when the email is viewed in Safari.

Steps to Reproduce:
Set preferences to dark mode.

Send an HTML email with the code @Media (prefers-color-scheme: dark) {body{background:#c00000;color:#ffffff}}.

Open the email in Apple Mail app.

Expected Results:
I'd expect the background of the body to be dark red and the text white, as it is when opened in Safari.

Actual Results:
The media query is recognised and read but all colours in the HTML are "auto corrected".  So the black background now becomes pale red and the text black.

OS 10.14.4 (18E226)
Mail Version 12.4 (3445.104.8)


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