[HELP] different screen resolutions!

Okay, I consider myself pretty knowledgeable when it comes to HTML and CSS as they are pretty basics languages. Though I have always had ONE trouble when designing websites and was wondering if someone here has a answer for me! So if for example you look at [url]www.youtube.com[/url] . I don’t think their columns are setup using % because if you stretch the page the columns stay the same size, and when the page is maximized, whatever resolution you’re on, everything fits. I normally use 100% width on my main container and set a min-width to a certain px size, but even then, some things just don’t look right at smaller resolutions/window size.. I’m wondering how professional web designers get the width to fit to your resolution but when you resize the window, it stays to that size? I’ve noticed on youtube (and other sites) they normally have an extra column (left side of youtube) with whitespace, and if you make the window smaller that WHITESPACE will get smaller but the columns were stay the perfect size! I’m wondering how to achieve this as it seems to be an issue with every site I program!

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