HTML/CSS/JS Code Design?

Hello! I’m a third year computer science major who mostly works with lower level languages (focus in AI so I also use more discrete ones) like C++ and Java which have common code design practices to improve readability and also show that you know what you’re doing. I haven’t had any courses in HTML/CSS/JS whatsoever but have started creating my own site.

I have to say, the code is messy.

It seems like a CSS stylesheet is just a never-ending list of styles for specific elements, and HTML is a bunch of nested things that cascade down. Obviously HTML is pretty straightforward such that it flows with the webpage, but little details such as when to provide a new line for attributes of a div (class, id, style, etc.) or even common naming conventions (snake, camel?) are the things I’d like to get into so that I can easily return to my project at a later date or even hand it off to someone else and have it be legible.