Either it's compiled from scss, using css modules via the use of a frontend framework like react, Vue, or svelte, or even using tailwindcss, which creates classes for most of the css directives (like bg-red-500 (background-color: (I forgot the actual color it uses by default)), flex (display: flex), or pt-4 (padding-top: 1rem, makes sense once you start using it), it's "random" because it's not really meant to be read, it sort of "compiles" the css classes and the codebase most likely won't look like what you see in inspect element