I think the answer here will explain everything. (Does this employer know/care? Am I about to dive into legacy practices? What does the bottom floor of the codebase look like?)
It draws a line.
Is asking coding style "religious"? I must argue: "That's, like, your opinion, man!"
> know/care
This is an implied project management question. (1) Can the employer even speak to it? (2) Does the employer see those who specialize on these areas as less important than other areas, in that they are fine with having no opinion on the matter?
> legacy practices
Did you not see this?
I picked HTML and (presentational) CSS (classes) for a reason, as they are boilerplate and they indicate whether or not Separation of Concerns bubbles up to management. Questions about HTML minification, the whole point behind preprocessed languages, etc. can be teased out with just one question.
It's like breaking into a network, looking at the codebase, and then combing for organizational and sociological judgments based on what you see. (LESS/SASS will comparatively more likely be documented. That said, would you take on an employer that leaves undocumented what can most easily be documented? — so it's likely they have lots of throw-away, unreadable, undocumented CSS. Do you want to work for an employer that is okay with "throw-away, unreadable, undocumented"?)
HTML is the lingua franca of the Web. Would you honestly work for an employer that calls this "petty stuff"? Tell me that. It's a tech interview both ways.
What if the employer responds, "That's petty stuff. We hire you to make that decision. We don't care. See the forest"?
You can find any person on the street who might say this. So why are you dolled up in a suit and tie yet again to be told "What you care about is irrelevant"?
Or what if the employer says, "I don't really know, but I'm glad you think about very finely detailed problems..."?
Generally my belief is that interview questions should fish or have the structure of getting you hired on the spot (http://pbfcomics.com/81/), where in asking them you've maximally described yourself but minimally given the employer the opportunity to fail. (Again, you don't care about your lingua franca of the Web? Go hire someone who has no opinion on this like you do.)
One positive thing that comes from your example is, if they know too much about that it means there is a whole lot of micro-management going on.
We like dialogue, as socially conscious beings.
Look at what the question contains: "presentational CSS classes in the markup". That's Separation of Concerns, not "stylesheets."
You're begging the question. And it's one question that can easily be generalized as a format-question: look at the operative words "use" and "utilize". Look at where they appear in the sentence.
Are those even exclusive?
One of the projects I work with uses Ace “responsive admin template” (paid theme from Wrapbootstrap). In its styles, declared variables and nesting are used unpredictably, as is indentation and other whitespace, which leads to awful readability and flexibility. It does utilize LESS, but it also uses presentational classes (least of its problems).
Pure well-structured CSS can be much better. LESS offers some useful possibilities, but also a lot of new ways to shoot yourself in the foot.
My point is—what OP wants (I guess it's readable, elegant, maintainable code) depends more on coding standards than tools used.
It's a fishing question.