Do your really, truly have a compelling and significant reason to worry about the indenting of content in the "body" portion of the page that comes from your database? Client browsers are not going to care about indentation -- they ignore it -- and the web server certainly won't care about indentation.

In the world I'm familiar with, the only humans who worry about indenting of html content are the hapless (or hopelessly compulsive) programmers who must sometimes wade through the html content to locate and understand the points where their html generation processes are going wrong. That's sort of an "ad hoc" need for indentation -- if the html is being created correctly, humans don't have to read it, and indentation is irrelevant.

(If humans need to edit HTML data manually, then indentation is a Good Thing, but the whole point of using a database and a template system is to make manual editing completely unnecessary.)

So please explain why indentation is so important. We often get questions that demonstrate the so-called "XY Problem", but I wonder if this might be a case of an "imaginary problem"...