It seems to be that the background colour value is set to `rgb(1,1,1,0.65)` and is missing the alpha channel in the attribute.

I made an identical page using `rgba(1,1,1,0.65)` and it looks better on iOS.

https://countdownto.xyz/c/jnfztcj0

This seems to be only a WebKit issue, you can produce the same results on desktop Safari. Other browser engines must detect when an alpha channel value is used with an `rgb` CSS attribute and update that attribute to `rgba` accordingly as an assumed fix.