There are three different level of CSS styles that are applied to elements
The initial styles defined in the CSS spec (Formal Definition), the styles specified by the browser (User agent stylesheet) and finally the custom styles specified by us
initial
Reset the properties to the formal definition values
inherit
Inherit properties from parent that are not inherited from default
Font properties are not inherited by form elements setting font: inherit will allow them to use the fonts that we have defined
unset
If element inherits properties that sets itself to inherit else sets itself to initial
On an element we can set all: unset this will cause inherited properties to be inherited and the rest to be set to initial values
revert
Sets the styles to the default specified in the browser