seems custom font doesn't appear in RTL mode when the site opens up in mobile responsive
Then, the custom font appears in the LTR mode?
When I see your blog, the vazir font loaded well
I just checked that the font not loaded to your site.

@Gictorbit Bro, I checked that you didn't' added the custom_css param
In your params.toml file
...
custom_css = ["css/font.css"]
...
problem solved thanks.
I forgot to add it to parms.toml