It's a great introduction, a nice summary. Consider everything comes from what we already know: Nature. We simply try to replicate it and accommodate some details of it to specific cases.

System could be a possible output but does not need to be. I'd define Design as a process to get a specific and defined outcome. Otherwise, when inspired by emotions and feelings, it could become art. There's no line defining the two, and in most cases both happily coexists.

So let's think of Design as a process, more than a system. Engineers, like anyone else, define system through design.

Colors, grid, ia (information architecture) —i'd add shape in this list, I'd remove typography, as are common shapes we attribute common meaning to— are core elements organized and categorized in systems. Not even sure grid belong here. That's to satisfy simple minds and provide a sense of order we could not reach otherwise. There's order in the sky when we look at it at night, we perceive it as beauty, we cannot say it's organizes.

Tools: are just tools, the medium used to translate ideas into reality. They come and go, one can be a designer simply mastering pen and paper.

Design is often defined as visual design, in web and print. But it goes behind that #384007 ¹. Creativity is the juice feeding it. Feel it, make it flow, someone will attribute you the designer tag, if you don't do it first.