Using custom CSS, you can add a colored background to your posts without editing your posts in other ways and without changing the background of the rest of your blog's body.

But you don’t need to use it, and your sites can still look good without it. How Do CSS and HTML Work Together? If you learned about the web a long time ago, or taught yourself the basics, you may be ...

WordPress' built-in editor has an HTML mode that lets you override the background color of a post by changing its CSS (Cascading Style Sheet) background-color attribute to the color of your choice.