I have a web page at http://form.kr/q/swap5/
The page works fine.
I like to change it for making the main content of the page just under the button related.
The page at http://form.kr/q/swap06/ is one of my trials for it.
I tried “z-index:0” on the main block and “z-index:1” on the button related blocks.
I want the main block is being located under the buttons and their contents.
Do you mean that you want the content that is revealed to sit on top of the main content of the page rather than displacing it?
If so then you need to remove the hidden divs from the flow using position absolute when they are revealed.
Have a go yourself first but remember that you will probably need position relative on a parent in order to place the absolute element where it needs to go.