Tools for UI with complex data entry

There has been much discussion recently on backend or php web serving on
IBM i, but not much about UI (user interface).
Looking for a css framework or tool for data entry grids that works well
across current browsers and screen sizes. Would like something where
someone else is tracking all the browser and language enhancements /
issues.
Screen panels involve large amounts of data entry (multiple names,
addresses, dates, phone, and plenty of other columns.
Current CSS is older, doesn't support hand held or tablets, and funky
screen sizes.
Not a site or UI for pretty pictures..
Some may think this is not a Power i issue, but for web enabled systems
where i is doing it all, it needs an answer.
Jim