If you want to try your hand at making a parser game, I’d really recommend just making a start and seeing how it goes. I found it daunting from the outside myself, but was amazed how easy it was to simply write “The X is a room. The Y is a container in the room. The Z is an object in the Y” and end up with a completely playable result. Obviously you’d want to describe all those things, and probably have connections to other rooms with other objects, but the basics are trivial to grasp. Those snippets that seem so incomprehensible will almost inevitably be things that other people, possibly people who are much more confident with Inform were themselves struggling with. You probably won’t run into that kind of difficulty unless you’re already feeling ambitious.
I know you said elsewhere you were tempted to move away from Harlowe, but Harlowe offers some very easy methods of styling your story without touching CSS if you don’t want to. Simply make a passage with the special tag “header” and then put macros in there that style all the text, or the entire page background. The toolbar in the editor makes this quite straightforward even if you don’t know what to type. It’s pretty powerful too! (This may well be possible with story formats other than Harlowe, by the way - I’m just not familiar with them myself.)