Looking for an old app/data that controls window furniature

About mumble decades ago I found and used an app/process which lets me choose an alternative set of furnature items (top bar, sliders, etc) for desktop windows. Did this to get an appearance I find clearer and neater. I then write a simple app that applies a new set of these furniture sprites, and have used that since.

However I now need to alter the appearance of the desktop windows on a machine used by my better half. I’ve adjusted the screen mode, etc, to make the content of windows easier for her to see. BUT I also need to get bigger, clearer slider bars, etc, on the windows. I’m pretty sure the old resource set I used did have some ‘large clear’ sets.

But I can’t recall the name of the original collection of sprites, etc, or where I got it decades ago.

So: Anyone recall this, what it was called, and where a copy may be nowdays?

Via a search engine I’ve now found this.

https://www.riscosopen.org/forum/forums/11/topics/19246

but as yet I’m not sure how to use it!