I took a look at the scripts, and they’re a bit more involved than that. For instance, in some cases they change the text of certain elements, presumably where the original text contains information OP described not wanting to see. In other cases, nodes are selected for their text content. It’s conceivable that some or even most of what the scripts do would be achievable with CSS, but probably not all of it. And it would probably require a level of CSS sophistication beyond OP’s start with JS (and likely beyond the CSS skillset of many otherwise experienced programmers).

All of that said, and I mean this kindly… I think there is an aspect of your comment that comes off dismissive, which is an implicit why did you choose X instead of Y? that a novice programmer likely couldn’t be expected to answer meaningfully. OP articulated very clearly what problem they set out to solve (impressively so! much more effectively than many Show HN submissions from seasoned devs). They also explained clearly how they used an existing tool designed for solving similar problems.

It’s certainly possible they will benefit from learning about different techniques to address some aspects of the problem. But an interrogatory introduction to why those alternatives weren’t chosen can be rather intimidating.