For a few years, I have been using GTML an HTML pre-processor to maintain a consistent look for my small sites. If you are interested in using this tool be sure to avoid versions earlier than 3.5.4 otherwise nested Boolean conditions will not work correctly. Unfortunately, version 3.5.3 is easily encountered on the Web. The link above points to what appears to be the most recent version.
Since GTML is a Perl script, an interpreter must be installed. In Windows, I use Strawberry Perl. However, with that combination, the following warning appears
Not quite knowing what I was doing, I followed the advice and changed line 1613 of gtml
from
to