help me with css and dive tags.

hi
i need a help with using css & div tags 4 creating my webdesign.
i wana design a Joomla! template with dive tags and...
the problem i have is to use dive tags inside other div. the insider div is my content div, where my content is showing in it. like my menus, pictures, articles and..
i show u a sample here. in my sample u can see how the insider div tags are growing oversize and my parent div do not change it's size.
i wana the parent tag change its size when the content div grow bigger.

this is my sample:

thanks every one who can make me happy with helping in it.