Impressed your client knows what CSS and JS are. Glad mine don't!
Downloading from websites is sometimes the only option. They might be minified or otherwise compressed. A beautifier can help but isn't as good as the original. If either were compiled from something else (e.g. Dart for JS or SCSS for CSS then a lot is lost).
@George An increasing number of my clients are larger companies with internal marketing or tech staff that I'm working alongside so they know their stuff. Thankfully, this was a WordPress site with minified files being called via query strings. It was actually pretty simple to grab everything for them.
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