Dear Adrian,
what you’re looking for is line 8 in the “custom-styles.php” file in the theme folder (wp-content/themes/Fuji) ;)
In case you want to change it via the WordPress admin, you can also insert the following line at the end of the “style.css” file (opened by default when you go to “Appearance – Editor”:
.normal, body, input, blockquote { font-size: 14px !important; }
Sincerely,
Andrew | Satori