Alter Single Post Background Color
This is a Developer Level doc.
If you're unfamiliar with CSS and/or editing files, codes and templates, as well as with resolving possible conflict, please seek help from a professional. Under our Support Policy, we don't provide support for modifications and customization.
By default, your single blog posts will have the same background color assigned via Appearance > Customize > General Options > General Styling.
If you wish to change the single post background color, use the following CSS snippet:
/* Single Post Background Color */
.single-post {
background-color: #fff;
}
Adjust the background-color value per your need.
All CSS snippets should be added via a child theme's style.css file or using the built-in Custom CSS panel.
Useful Link: HTML Color Picker