The Typography Handbook says the following:
The Gestalt Law of Similarity states that entities that look similar tend to be grouped together. For example, if all clickable texts are sky-blue, the audience will assume that all textual content that is sky-blue is clickable.
In typography, the law of similarity just means to keep your styles consistent on elements that serve the same function. Group of elements should also look similar to other groups that serve the same function, for example: the visual styles of one blog post should look similar to another blog post. On the other hand, elements with a different functions should not look similar to one another.
However, it violates this very law in each "further readings" section, which has an opposite color scheme to the rest of the page:
Same applies to the table of contents, which uses black and gray colors for anchor links (or, more accurately, #333 and #333 with 0.75 opacity):
The Typography Handbook says the following:
However, it violates this very law in each "further readings" section, which has an opposite color scheme to the rest of the page:
Same applies to the table of contents, which uses black and gray colors for anchor links (or, more accurately, #333 and #333 with 0.75 opacity):