Since a steadily increasing number of websites use advanced effects that are dependent on uniquely expanded versions of the baseline scripts, Codepen's Editor View makes it a point to display any special libraries and extension languages used. In a particular project showcasing what the author calls a "fancy scroll," for example, the file fulfilling the role of the project's native CSS document is an SCSS document, which supports a broad array of additional and more specific functions.
The project showcases several photographs that dynamically replace themselves based on how high or low the scroll bar is, and each photo is accompanied by a text description that fades into existence only when the user scrolls toward its position on the page. Each photograph is changed into a version in which the people pictured on it are muted in color and the background behind them is replaced with a pattern with purple and yellow shapes. This effect does not use particularly elaborate syntax, however; it is shown that there are simply two versions of each photograph, with one overlaid on top of the other. The smooth transition used to "wipe" away the photograph on top to reveal the version underneath can make a striking impression on viewers regardless. For more information click here https://v.redd.it/4ksv0s2rg0731.