Is there a term for this distinction of sweet categories?
No, there is no standard categorization on these lines. You are just creating a personal categorization in your head (which is not a bad thing in any way - that's how everybody's mind works) and you are attaching an association to brightness/darkness which is mostly personal, but might be close enough to a shared experience/language use that other people could understand it if you gave them sufficient examples. 

The prototypic quality of your "dark" category seems to involve the presence of caremel-like notes and maybe some phenol-based tastes. (To check if phenols are defining, ask yourself: is liquorice a good example of the category, maybe a better one than pure sugar?) The presence of fat also seems to play a role. 

The prototypic quality of your "clear" category seems to require the combination of sugar and acid, and also having water present, as opposed to fat. 

I said above that these are not usual categories, but they are to some extent recognizable when explained. More common descriptions are for phenolic compounds to be associated with "earthiness", to some point maybe also caramel may have that association. Fats tend to be associated with density and heaviness. The coloring of many caramelized or phenol-containing foods is also dark. So I think that this makes your category name somewhat intuitive. 

As for the "clear" category, on some occasions acid is indeed called "bright". And water is indeed clear visually - which might strike you as irrelevant, but actually our brains overlook this kind of separation when building associations. 

So I would think that your categories are intuitive enough in the sense that, if you were to give people examples from above and then pressed them into assigning a bunch of new items to these categories, there will be a noticeable correlation in the assignments. But if you also ask the people if they use these categories or know of them, I would expect that almost nobody does. 

The closest widespread classification which is somewhat similar is the division of "top", "middle" and "bottom" notes in perfumery. But besides not having made it into cooking, that categorization only has some overlap with yours - they are related, but not too closely.