The new Blocks include baseline support in all themes, enhancements to opt-in to and the ability to extend and customize.| WordPress Developer Resources
WordPress 5.8 comes with a new mechanism to configure the editor that enables a finer-grained control and introduces the first step in…| WordPress Developer Resources
The background-size CSS property sets the size of the element's background image. The image can be left to its natural size, stretched, or constrained to fit the available space.| MDN Web Docs