What Makes a Website's Design "Modern"?

This is an open question to the world of Webdev:

What makes a website's design "Modern"?

I've searched Google multiple times for style guides and concepts, I've looked at story-boarding for sites and different icon-sets that are used for Mobile-first sites that have all but been incorporated into the standard for what people associate with a function on a web platform.(external links, hamburger menu, etc.)

But even still there's always so many concepts of what a Modern design is or was as this seems to change like the wind.

It makes sense that it evolves and changes as the term Modern a decade ago often doesn't hold the same value as it does now.

But what is "Modern" for mid 2021? Is it the newest features that run on the newest browsers? Is it fancy CSS that can do things that were unimaginable before?

If you asked a Front-end Developer, Back-end Developer, and a Web UI/UX Designer what the current concept of Modern is, what would they say?

I know this is a lot of questions but I'm absolutely curious to find out.

If you have any concepts yourselves you are willing to share, any answers to the questions above, or general feedback on what you think is the best way to understand the "Now" factor of Modern design please do leave a comment start a discussion I would love to hear what you have to say.

Thank you for reading and I hope this brings up a few interesting answers and allows some food for thought on the questions.

Cheers
-A Curious Coder