To make a layer transparent

I have a question about css. I use blogger for blogging. I have modified the template provided by the blogger. Now i want the main section (main-wrap2) to be transparent so that the background can be seen. When i use opacity the post get transparent and it is very difficult to read. What should i do, so that only the back ground is transparent not the posts or pictures which i post.
the blog is : http://manojkumarpv.blogspot.com/

 

background:transparent; usually works, but uhh.. your text will be hard to read on that background if it is transparent

 

But, there is a way. I have seen sites like that

 

Seen sites like what? Explain what you're trying to do.

You can use opacity or you can use background:transparent, though opacity:90 or 95 will make it easier to read.

 

Well, I think u r right. The site which i have seen, uses a background that doen't make the word unreadable. Any way i've dropped the idea.