'Early' websites [0] were very linear, text-heavy affairs. They still had images, of course, just a pretty basic 'full width, top to bottom' layout. Authors quickly realised you could abuse tables for layout, but rudimentary alternatives used frames. They just relied on default styles. Next time you're working on a site, just drop the stylesheet. That. That's what sites looked like.

[0] I'm talking mid-late nineties here. I don't know, off the top of my head, what level of CSS support or style-in-html support there was, I'm just talking about very hazy memories of what they looked like.