Your Tumblr theme sets the background color ... box labeled "Add Custom CSS": Replace "yellow" with the specific color that you want to apply or with the color's HTML code. Click "Update Preview ...

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.

Some argued that it was an unnecessary introduction to "Web" technology to the native development experience, and others that it simply isn't the right solution to the problem ... CSS as an extension ...

In the following CSS example, the background color is set first as a fallback. Then if the browser supports the gradients and it finds the valid CSS syntax, it will use the gradient instead: There are ...