I strongly doubt a reasonably designed "semantic" design can be half-forgotten after taking a break; the fine points of the implementation of sophisticated rule

I strongly doubt a reasonably designed "semantic" design can be half-forgotten after taking a break; the fine points of the implementation of sophisticated rules (e.g. why did we put the left border on the parent and the right border on the child) might suffer from obsolescence and lack of documentation, but the markup structure and the names should be obvious. Forgetting what plethora of non-semantic classes should be used on what elements seems a far more likely problem.