Add white background and image border to content on Wordpress site

We are creating a Wordpress site. Currently when you add content to a page, there is no background behind the content. The only way we can add content with a background is to use the template editor, but we want the white background and image border to show up for all our pages. Here's an example: [login to view URL] We need the content to look like the content on this page instead: [login to view URL] We need it to NOT affect the transparency around items such as the three feature boxes on the home page.