MikeR wrote:1/ With the x3 popup on the "desktop" version I can exit the image and go back to the gallery just with a click outside the image. On the mobile (Iphone and Ipad, I don't know for other tablets) I need to touch the cross button (if I touch outside I can swipe).
Did you try swiping down or up? or even pinching? We use industry-standard UI methods for closing the popup on touch-devices, and they are quite intuitive.
MikeR wrote:Is it possible and simple with css (maybe) to have the same functionality on mobile ?
There are reasons why the area outside the image (which very often, is extremely small on mobile), does not close the image on "touch". First of all, because there are already methods: close-button, pinch, swipe-up and swipe-down to close the x3 popup. Second, because touch outside the image area is often part of a users swipe movement (navigating between images). Have you checked the PHOTOS application on iphone or ipad? You will find the same behavior. Personally, I think you should trust that we are experienced and passionate UI designers, who have put a lot of love and thought into the X3 user-interface and how it works based on best modern practices.
MikeR wrote:2/ The image's title is centered on desktop and tablet but not on smartphone, can you tell me which css must I change ?
There are UI reasons for this also, do you really need to change these things that we have done for good reason? It's rather complex responsive code required. Amongst other things: Although a desktop has a wide screen, the visitors field of view is much narrower (similar to why text pages should be limited by a narrow width). Therefore the text often looks best if it's centered on large-screen devices, as long as the description is not multiple lines. On small screens however, this is obviously not the case, and a user will look for text from the left aligned from where the image starts ... Also add the fact that there is a big change they are using their right thumb to interact.
Also, are you thinking that users will be comparing the alignment of text between large- and small devices? These devices ARE different, and users use the completely differently, and that's why things work slightly differently. The CSS is there to edit, but we can't provide custom hacks for everything in X3 which (subjectively) has no benefit to the visitor. This is how X3 is built, smartly.