Customizing Html in outsystems

 Can I have my own html's if i am not able to get the exact UI like i want using your existing widgets or rich widgets. Using css and javascript is not enough.
You can, but you should not. The Outsystems Platform provides you resources and features to speed up the development of your applications. You pay for it, so use it. Why would you give up everything to back to hard code? 

You can customyize everything in platform, create your own layout widgets, injecting html code and javascript with expanded inline expressions... to create your own UI will demand a lot of work and will not be so simple to maintain it as would be with the platform framework. Think about it.

Andre i beg to differ . i am personally going through immense pain  in a project am doing with generate a dynamic,signature ,biometric, image and biodata on top of an id card image that will blend in the background( ..the idea is to generate a highly customised employee smart card .the html and css combo is what has kept me for days in the project .the high abstraction from the html code is not helping me. i wish SS had a full blown html editor like sublime,were i can see all html code and ability to modify it and link it to css like visual studio.building UI visually and using css to customise is very very difficult for me and am stretched to the point of giving up on using outsystems for this particular use case and do everything in mvc were i have access to the html.