How to Change a Sidebar Background Color With a WordPress Theme

1. Log in to the WordPress dashboard from the wp-admin directory of your website. Navigate to the 'Appearance' screen and click the 'Editor' link under 'Appearance' on the left-hand menu. Click the link to your sidebar file under the 'Templates' heading.
2. Find the div or section tags that wrap around your sidebar in the code. Add a pair of wrapping div tags if you see none, and give them an ID name. Here is a sample of sidebar code:



In the above example, you would need the ID name 'primary' from the first div tag. Save the file if you changed it.

3. Open the style.css file in your themes editor by clicking on its link under 'Templates.' Look for a selector such as '#idname' where 'idname' is the ID name of your wrapping div or section tags. If you do not see this selector, add it to the bottom of the file. Edit your CSS code so it looks like this:#idname {background-color: #cecece;}The above code shows how the background color is set for the div or section with an ID name of 'idname.' Your selector may include other property-value pairs.
4. Change the value of 'background-color' to the code for the color you want to use. You can use named colors like 'red' or 'purple,' hexadecimal color codes like '#ff0000' or RGBa (Red, Green, Blue and Alpha) codes like 'rgba(255, 255, 0, 0.5)' to specify semi-transparent colors. Save the file after you finish.