Differentiate the documentation pages for new users.

Hi, this is not a high priority issue but it's one I just want to have here.

When I was learning Rust for the first time, the documentation pages confused me, especially since the entry point for a lot of users is just googling "rust" + "some stuff" and see if documentation exists.

So Googling "rust rand" gives me this page https://docs.rs/rand/latest/rand/ which has the same look and feel as the official rust documentation page. https://doc.rust-lang.org/std/

Except for a slightly different logo and the top bar.

But for a new user that is going between pages, to them this is the same page. And then they need to learn that, no, rand is actually a library.

So, to help out new users. Can docs.rs or the official docs page do something visual to differentiate them from each other.

Color, layout, highlights, something obvious when you enter the page and scan around.

Something that tells you immediately "We're not in Kansas anymore."

<3

Compare the docs.rs/rand page with the official Rust standard-library documentation linked in the issue, focusing on how a new user distinguishes them while scanning. Define a concrete visual direction and a clear completion criterion: users should immediately recognize whether they are on docs.rs or the official Rust documentation.