Might take a look into SGML: renders server-side and in the browser, based on static files rather than databases (though you can fetch from DBs, services, or ot

Might take a look into SGML: renders server-side and in the browser, based on static files rather than databases (though you can fetch from DBs, services, or other resources as well), based on the ISO standard that kicked (and still encompasses) all of HTML and XML, powerful templating without reaching Turing-completeness, markdown and other custom syntax support, HTML-aware injection-free templating, finite-state automata for stylesheets and other context-dependent templating ...