[icameron]

Wix has a responsive layout from what I've seen as a casual maintainer of a rather large Wix site, which was originally built by a non-coder. Maybe it was part of the template he used, but a row of 3 images on Desktop automatically becomes a column of 3 images on mobile, and the top menu turns into a hamburger. You can also switch to mobile mode while editing to adjust the layout of the mobile version.

[andrewl-hn]

It's more complicated than this. You design a desktop version of the site in Wix, and it automatically generates a mobile version. Some widgets like image galleries and lists are responsive, but they have hardcoded rules.

So, it's not a fully responsive templates, but they are good enough for most websites.