You should design with constraints. That's why I think most websites should probably be black and white anyway. But in the 90's we had no color displays so black and white is all you had to work with.
Most of this website are documents. They only need to achieve readability with hierarchy and a bit of layout. The content is front and center. So most of the page is typographic. The choice in typeface is probably the most important for visual atmosphere. If you say System 1 you automatically say monospaced.
The text is set in Simplon by Swiss Typeface and the decoration text is set in Redaction by Titus Kaphar and Reginald Dwayne Betts. A monospaced font might not be the the best choice for extended reading but you gotta keep the hacker feel alive somewhere.