I´m planing to use Cordova v3 to develop a generic application to target mobile devices using HTML/CSS. Which is the best solution in order to reuse most of the html but having
try you using twitter bootstrap, http://getbootstrap.com..
might be a solution for you, because twitter bootstrap is framework for html and responsive code for all device,, check resolution web in http://quirktools.com/screenfly.. and you can convert web with phonegap..
As you said "but having the visual style for each mobile platform?" I understand you are searching for a native look in the apps. the other answers are good frameworks however unless you want to spend time tweaking css they will not look similar to a native UI (visually).
I have worked with Twitter bootstrap and jQM. So far so good but for a native UI look I will go for the following options which I think are the best. These are my top choices after spending a considerable time looking for a jQM alternative as I am not really happy with it in specific aspects.
EDIT: I am adding two new options based on my experience and what I have found so far (ionic and onsen ui).
http://ionicframework.com/
Intended to develop hybrid app using Angular JS is a really gem. I have been working with it and it has really helped me to develop faster than when using jQuery.
It also was UI elements that you can use out of the box and they are styled properly for iOS and Android although I think its style is more iOS-lish.
http://s.onsen.io/
I have not work yet with it but it looks like a really complete UI option for hybrid apps.
http://www.kendoui.com/mobile.aspx
http://phonejs.devexpress.com
http://chocolatechip-ui.com
http://www.appgyver.com/steroids
If you feel like a adventure explorer take a took at steroids, which is cordova compatible and they claim you UI will perform as well as native. It is quite new, I haven´t give it a try but I seems promising, however as still is not widely used I did not decided to use it as having a lot of people using it is helpful when you face problems.
NOTE: If other have interesting alternatives to experiences with this or other UI frameworks for cordova/phonegap please share!
My suggestion would be jQuery Mobile which supports almost all mobile devices in the market.
For the list of supported devices: http://jquerymobile.com/gbs/
1) It provides a native feel for each device platform. 2) Supports all platform 3) Easy support and 3rd party plugins
It's been said by some that jQuery mobile might be slow.. but you can tweak its settings to make it good.
You could use Onsen UI. It claims to be faster than jQuery and has its own theme roller and is built to be compatible with PhoneGap/Cordova.