How to correctly set the background, font color for email template, for correct display on iphone xs in gmail application?

Question

gmail

Good day to all.
Faced such a problem when testing the layout of an email template, the background is not displayed, and the font color is different on the iphone xs in the gmail application
Tested the layout on the iphone 6, 8, on android smartphones, applications and the web version - everything is displayed correctly, the background, the color is correct, and xs has a completely different color rendition, what could be the reason?
If anyone has encountered a similar problem, please write what is my mistake and how to solve it.
And also if there is an example of an email template that is displayed on the iphone xs in the gmail application, it's fine, please show the code.
I want to understand for myself that I didn’t type up the letter correctly, or is it due to some settings in the gmail application on the iphone xs that such a display occurs.
Layout of the letter here:https://str3lok.github.io/mailer/
View on iphone xs: (photo not attached to question)
www.nsfpic.com/data/q4/q4ckeg/photo_2020-01-17_12-...
www.nsfpic.com /data/q4/q4ckfh/photo_2020-01-17_12-...
www.nsfpic.com/data/q4/q4ck8j/photo_2020-01-17_12-...

Answer 1

The question is closed.
Perhaps someone will need a solution to the problem.
On the phone, a dark background is selected in the settings and because of this there are some defects when displaying mailers. When choosing a light background - no defects