We can select different styles for Mobile, and Desktop devices.
Style for Desktop:
Style for Mobile:
Different styles: not displaying as expected?
If Styles for desktop, and mobile are not selected as expected, it might be due to a cache issue. Some of the cache(cache plugin, servers side cache) creates only one static file per page, and the same page loading for desktop, and mobile.
There are two ways we can fix this issue:
Method 1: If there is an option to enable to detect devices(separate cache for mobile) on cache plugins installed on your website, enable it.
Method 2: Check this, If styles for mobile, or desktop are not displayed as expected(due to cache)