Vaguely. I know the basics and am actually studying CSS at the moment at University.
Even with only knowing the basics at the moment I can say one comment - "Thank god for CSS". I don't know how we managed before it existed!!
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But seriously, it is a god send and makes development a lot easier and the way it was originally intended - formatting and content seperated! I use CSS on my website and it makes things a lot easier. I would recommend to anyway to avoid the depreacted tags in HTML and use CSS where possible.
Have you given up with the Java then?