Selectors are used to select the element(s) to be styled. Properties are the ways of styling selectors and use values to accomplish styling.
The :out-of-range pseudo selector selects a number input box when the number entered is not within the specified range defined in the HTML code. The :focus-within pseudo selector selects an element if it contains children that have the pseudo selector :focus.
The filter property changes the rendering of an image, background, or border to include filters such as blur and grayscale. The order property can be used to change the ordering of flex items to an order different than the one given in the source code.
Selectors select the element(s) to be styled. Properties are the methods of styling that are applied to the selector.