We have been doing this a long time, since 1994 in fact. Things have progressed a long way since then and we have been on board the whole way.
The way websites work is substantially different now than it was then. Now most websites work with a combination of various scripts, databases, and many other technologies to create each page on the fly. Which is great when you want dynamic content. In the good old days we used to create each page individually and link them together. A rather static and un-responsive result.
One used to get away with knowing html and basic internet technologies. Now there are any number of ways of acheiving the desired result. We don't pretend to be experts in all these technologies and methods, "Jack of all trades, master of none". Though we have much of the expertise in house we have an excellent team of specialists we can call upon if needed. Thus there are few challenges we wouldn't be able to match.