To change the heading fonts, first import the google fonts and then put this CSS in Common.css or Fandomdesktop.css
main.page__main {
font-family: YOUR_FONT; /* This will change the article page font */
}
h1.page-header__title {
font-family: YOUR_FONT; /* This will change the title of the page */
}
.page__main h1,
.page__main h2,
.page__main h3,
.page__main h4,
.page__main h5,
.page__main h6 {
font-family: YOUR_FONT; /* This will change the headings font */
}
.fandom-community-header, /* This will change community header font */
.fandom-community-header__local-navigation, /* This will change community header font */
.fandom-sticky-header__sitename /* This will change the font of sitename in the sticky header */ {
font-family: YOUR_FONT;
}