I invested a lot of time in learning and deploying Flex. It's been a lifesaver when I had to code quick visualizations, dashboards, analytic tools, db interfaces, etc.

Now I would like to transition over HTML5, but it seems that all the tools and frameworks are incomplete, not easy to integrate, etc. and now I need to know javascript, html, css, etc. and the language to code the backend (In my case usually very CPU intensive). With Flex I only needed to know as3 and my backend language.

What would be best framework similar to Flex that would abstract the ugliness of javascript, html and css? It's not my idea of a fun time to fight layout bugs and different javascript/css/html implementations.