How can I download a whole website full of comic book media?

The website i’m talking about is https://comicbookplus.com/ .
I love it. They have thousands of public domain comic books.
I want to download the whole website in case the website ever goes out of business. (There’s no indication of them going out of business. I’m just scared of the possibility).
I realize I’d need an external hard drive with at least a terabyte of storage capability.
But then, what do I do? How can I save that great website forever? So I can read all their comic books off-line?