Web Designers, Please Stop Reinventing the Wheel
This, right here, is the culmination of our frustration with modern Web page design: the website for something called Material Shell. There is so much wrong with this, I'm going to have to take this step-by-step.
Using CSS for Meaning
The second problem I see is just how the page is laid out. See those two iframes on the right? Yeah, they're not iframes. A little Inspect Element reveals that all of the layout is nothing more than a collection of <div> and <span> tags. That's because everything about this website's layout is controlled by CSS. Try deleting the couple dozen or so CSS files with Inspect Element; you end up with a horrible, unreadable mess with random text all over the place. This is not what CSS is designed for. CSS is designed for visual styling only and must be optional.
By contrast, see what happens when you delete the CSS from this page (the one you are currently reading). First of all, it's only one CSS file, not dozens of CSS files. But more importantly, you will find that the entire website still functions as normal. You still have your header links at the top, your footer at the bottom, and everything else organized as it should be. Everything about the structure and meaning of this page is contained in HTML; that's what HTML is for. As such, browsers without CSS support (such as text-based browsers) will still work just fine. It just won't necessarily look as pretty.
Not relying on CSS styling is also essential for accessibility. Screen readers (which blind users depend on) cannot parse random CSS styles to figure out some kind of hidden meaning. They depend on HTML tags, and they can't get that from a giant cluster of divs.
The third problem doesn't ruin accessibility, but still, it infuriates us to no end. See the pages in this document? They're not pages. They're sections within a single page.
Look, I get it. We're not using dial-up anymore (or rather, most of us aren't; dial-up is still in use in some rural areas). You want to use those "fancy" page slide animations that are all the rage these days. I think it looks tacky and silly, wastes my time, and isn't going to age well, but let's just say that this design is the most marvelous thing in the world. Even if we accept that, I still find this design unacceptable.
This ties into the thing I was saying just a bit ago: HTML has a defined meaning, and this design flies in the face of it. The whole point of pages is to only send data to the client that's relevant to them. When you clicked on the link to this article, you didn't have to load every article I have on this site. You just loaded the one that you wanted to look at.
The counter-argument would be that in the Material Shell website, all of the faux "pages" actually belong on the same page anyway because they're all marketing babble. To that I say two things. Firstly, big pages of marketing babble don't belong on a home page to begin with. They belong on a dedicated About page so that only people who want to see marketing babble have to load it. Secondly, the page is clearly designed to encourage the client to use the table of contents (which it tricks you into thinking is a navigation bar) to go through the various sections.
Allow me to explain. It's not at all unusual or bad for a long document to have a table of contents. This sort of thing is the whole reason for section links. But this feature is designed for a single, unified document whose contents are all interrelated. For a simple example, let's look at our Rejected Libre Games page. This page has a table of contents to help organize the document by reason for rejection of a particular game. The key here is it's all a unified document whose sections are interdependent. This page cannot be divided into three pages and still remain coherent. Therefore, the table of contents exists to help with navigation without splitting the document up.
The Material Shell page, however, is a completely different story. This website's sections (which it tries hard to convince you are pages) are completely independent of one another and do not reference each other in the slightest. You could go to the "Tiling engine" section and not even glance at any of the others, and you wouldn't be missing a thing. All the context you need for it is there.
Beauty in Simplicity
There's a certain beauty to simplicity. I know it can be tempting to want to grab all the toys and play with them, make everything flashy. But what's cool now won't be cool tomorrow. We're old enough to understand at least that much.