Our tests confirmed that iOS and Safari works in the same way of other browser and operating system with custom styles.

If this don't apply, the problem is probably different and could be due to the particular template used.

If the Joomla template renders different classes or html structure for mobile devices such as iOS, the style rules won't be able to apply being generated on a different desktop version. To confirm if this is the case just try it using the default Joomla template.

Regards,

John