Every platform has their own little nuances, a Windows app will look drastically different than a Linux app; same goes for Android and iOS. It is near impossible to please everyone, and attempting to cater to everyone will more often than not results in sub par experience for everyone. While your tool chains may be able to compile to all these platforms, it may be a good idea to focus on one (or at most two very similar) platform(s), and provide a better experience for the targeted user group instead.