Hello! I am currently a software developer. I didn’t use FreeCodeCamp but I sometimes come and answer questions to help out - I like mentoring/helping.
I wouldn’t get too beat up about not having a portfolio website or not doing one as it really depends on what position or career path you’re trying to go for - it may not even be relevant. For example, for where I am at now we don’t even check for a portfolio website or request one, we request a Github and any work they’ve done (physical copies preferred). I would highly suggest worrying more about your social profile and Github than a portfolio website - they are nice to have but almost never get used to judge for hiring. I have hired at 3 different companies for this and not once did anyone on our hiring team even bother to really look at them.
To bring this back to your post. DO NOT feel ashamed to just go and Google code. Search for a navbar you like and then either try to build it yourself OR copy/paste the code and tinker with it. I can say this with justification - every programmer or developer out there Googles and uses code they find in Google searches at least a few times a week. There is no true way to knowing or understanding everything.
I do agree that Free Code Camp is a “tip in the iceberg” as there is so much more out there - but from what I can tell it is a work in progress and a code “get your feet wet” solution. I’m rather interested when they adopt Python personally - that’s what I am an expert in.