Yup.
Look at rive.app = :110percent: flutter.
Or https://web.nostrmo.com/ for a :nostr: app.
Discussion
ok, if you can build one codebase with reactivity to cope with small mobile screen up to 4k, i can sketch out the general spec of how the design will be on the 3 different sizes. i have already done a lot of work with this.
desktop apps that can shrink to mobile widths especially are handy when you have a dynamic tiling window manager, lets you stack little displays for apps that you want to watch but don't want big detail unless you want big detail
a great example is chat, btw. having a chat window in a side panel is so neat for collab, with a 4k display and sharing quarter sections of the rest of the screen.
there are so few really good UI designs in production unfortunately. i hate windows but the windows 8 paning system is so intuitive