Hi @anouchkab,
I am David, from Single Stroke. I would like to help Aristeides about your error with Pixie theme.
The Kirki_Fonts::get_google_font_uri usages on the theme has been dropped since Pixie v2.0. The last version of Pixie which uses that function is v1.2.1. We (Single Stroke) suggest you to update your theme to the latest version (v2.0.4) which work perfectly with the latest Kirki Toolkit. Have you any trouble during the update, please contact us via the support form as mentioned in the theme info.
Regards,
David