I have wondered many times.
Of course I can always use a browser but it’s overkill.
The same goes for yad or zenity, they pull in webkit which is a full-fledged browser engine, and at least yad does not have an offline mode.
I just want to look at some local HTML (incl. images) & CSS styling.
Those are great suggestions; I don’t use them only because neither is keyboard oriented, so I tend to vacillate between Luakit, Surf, vimb, and Nyxt (although the last still has serious hard-hanging issues and an obscene configuration).
On this topic, I’d be interested in a terminal browser that tries harder on the layout front. w3m, links, links2, elinks - they all work, but none focus on layout and rendering even as much as terminal Markdown renderers such as glow and hike.