Current XS

All headings have the same weight as the paragraph text, the only thing emphasizing them being their size.

Updated XS

Change made: Increase font-weight for headings based on their level

Motivation:

Because we are in the field of organizing knowledge, we need to take into consideration the psychology behind it.

One of the main reasons people organize knowledge is because they want to make it easy and fast to access it, either for themselves or the people they work with.

Easy & fast accessibility of information = easiness & speed in searching that particular knowledge. When people are searching for digital information, they don't read everything that exists on a particular page.... they scan the page. More details on this (link) source.

It's very hard to scan a page if everything mainly looks the same. Size is not enough to emphasize headers, especially when Sans Serif fonts are pretty thin even at a big size (on the Regular weight).

To better serve the goal of knowledge organization, we should increase the font-weight of most headings, keeping the current sizes.

To keep and increase the idea of hierarchy, the subheadings in a page should have the font-weight based on their level.