Also, disabling scrolling and using swipe for sections instead _at a font size that causes text to overflow_, depending on phone screen size, meaning a bunch of the site is _literally_ unreadable, since it's off the screen with no way to get there.
Reds people choose are usually between dark and light, which doesn't contrast particularly well on anything because for good contrast you need a dark color vs a light color.
Green, yellow, red or whatever hue is fine, as long as it's dark or light enough. Colorblind and non-colorblind people can see how dark or light a color is (luminance), but they might not agree on the hue. That's why WCAG contrast checks require luminance contrast and not hue contrast.
It's best to use a contrast checker because it's not always intuitive how dark or light a color is e.g. yellow and lime are almost as light as white.
I can’t read this site. Red background, dark grey/black text, is a terrible terrible choice for colors for readability. There were some words there but all I could make out were the header on my mobile phone.
