What are..., these things? Options

[smplyxme]

I see scripts and things for stylesheets but what are they, are they different from the regular way you code a skin?
And what is css, and what does it do? I see those alot, but i dont know exactly what they are.
Oh and one more thing, where can you get a variety of filters for your xanga, like where it edits the date or bold text. Where could i find filters for that?

[*mona lisa*]

This is another filter I know-

CODE

<style type="text/css">
div.blogheader, .caption {
filter: alpha (opacity=90, finishopacity=0, style=2);
}
</style>

You just paste it into your HTML Header. I guess you can try playing with the numbers to see the different outcomes.