I've long been a fan of Edward Tufte's work. I'm also a fan of old-style serif fonts, such as Bembo.
I happened across the R Studio Tufte Handout Style yesterday, and I was immediately struck by how much it resembles Tufte's books. It uses Tufte CSS and the open-source Tufte Book Font. ETBook is a “computer version” of Bembo that Tufte constructed for the more recent editions of his books, supplanting the lead type of the earlier editions.
I've adapted this blog's stylesheet to use ETBook and some of the other settings from tufte.css. It's not completely faithful; e.g., headings are bold, not italic.