Update customize-ui-overview.md

Author: yoelhor

articles/active-directory-b2c/customize-ui-overview.md

@@ -80,6 +80,7 @@ Review the following guidance before using your own HTML and CSS files to custom
   - Limited support for Internet Explorer 9 and 8
   - Google Chrome 42.0 and above
   - Mozilla Firefox 38.0 and above
+  - Safari for iOS and macOS, version 12 and above
 - Don't include **form tags** in your HTML. Form tags interfere with the POST operations generated by the HTML injected by Azure AD B2C.
 
 ### Where do I store UI content?