well thats the fun part as reading to and writing to files is the easy part with Stream Reader that will read the file just fine

i highly recommend you multi-thread the app with a safe threading module like background worker as to ensure the
application can perform more then one task at any giving time ensuring the application is capable of still doing functions while running another as to prevent the flaw in VB with (not responding only been able to run 1 task before doing another).

you will have to make a small library of html and css elements and assign them to id's so on the say xml file <button id"button"></button> ect its able to know what to do with the code in the xml so for the button ID its able to use CSS to style it with your predefine settings.

note there are quite a few elements to consider and plan, its best to plan on paper to work out or try n work out exactly what you need and work out the preparation for your work space as there are many ways you can do this some very easy with little complexity and others will allot of coding and debugging but remember XAML brings stuff to the table as well.


here is a youtube video that will give you a refresher on the basic, i find the https://msdn.microsoft.com/library/default.aspx library is the best source for info if needed .

https://www.youtube.com/user/TeachMeC.../videos?view=0

I wish you luck on your adventure as the rest is up to you.