A friend of mine is such a high level programmer he knows css back to front with the divs, ids, classes and the rules such as margin and padding, he knows his hacks and conditional comments when it comes to styling he would say hes a fairly advanced developer, he told me he can also do javascript and php too but hes had no formal training, question is how hard id it for 'one' to be a great developer learning real hard code like css and html?