How to override a CSS class within a content div

I want to reimplement the property margin-right in a bloc whitin a content.

this is the content id css:

#content h2 {
      margin-right:2px;
            }

this is the bloc class css:

    .bloc h2 {
margin-right:0px;
                }开发者_如何学Go

I want the margin-right of the ".bloc" css fires rather than the "#content" css

Try !important, like this:

.bloc h2 
{
    margin-right:0px !important;
}

You could try this :

#content .bloc h2
{
    margin-right: 0;
}

I'm not sure I understood your question perfectly well, especially the last sentence...