consists of a property and a value it is to be set to
example: box-shadow: inset 0 3px 7px #f6f7f7;
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ruleset
Front
describes how input elements should look. it consists of a selector, which is the element or elements that will be targeted by the declarations that follow.
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selector
Front
CSS provides a rich set of selectors that give you precise control over the elements targeted by a declaration block.