How to be selective with css?

Say I have a home page which I’ve chosen to have a transparent background but then I don’t want to have a transparent background for the rest of my pages.

How do I do this and how do I know which styles to use.

My home page is full width with the content background tranparent -
But the content in the other pages needs to be white ( so not to show the dandelions )-

I can get the whole page white but not sure how to do it just for the content area.

Easy. Just add a class to the body element on your hove page. E.g.

<body class="home">

Then set the styles you want just for that page. E.g.

.home { [I]styles here[/I] }

or perhaps

.home .content { [I]styles here[/I] }

depending on what you want to style just on the home page.