The Nth ______ selector is one of the most confusing aspects of using CSS. Fill in the blank.

The Nth child selector is one of the most confusing aspects of using CSS. This selector allows web developers to target specific elements based on their position among sibling elements. The challenge stems from the fact that the :nth-child() pseudo-class takes a variety of arguments, which can lead to confusion about its implementation.

For example, :nth-child(n) selects every element, while :nth-child(2n) selects every second element. The situations can become even more intricate when you factor in offsets, like using expressions such as :nth-child(2n+1), which selects every odd element.

Understanding how the counting works (starting at 1 and considering only child elements) and the differences when using related selectors (like :nth-of-type()) can make working with these selectors tricky. Thus, much attention is required to apply them correctly and to anticipate the resulting styles on your elements.