the cascade definition

The cascade refers to how CSS determines which styles are used in a website when styles conflict with one another.  To determine the case 1) Locate the declarations that include a selector that pairs up with an element 2) Organize by weight (importance) the declarations associated to the element 3) Remember that rules containing !important are weighted more than rules that are not marked with it.  Therefore organize by origin the declarations associated with the element.  The three origins are user agent, reader and author.  Typically an author’s styles overrule the reader’s styles.  However, !important reader styles overrule !important author styles.  A user agent’s default styles are overruled by both author and reader styles.  3) Organize by specificity the declarations associated to the element.  Elements with a lower specificity have less weight than those elements with a higher specificity.  4) Lastly, organize by order the declarations associated with the element.  A declaration has more weight when it is located further down in a stylesheet.  If declarations are located in an imported style sheet, they are given the status of coming before other declarations in the style sheet that imports.  They therefore do not possess as much weight as other rules in the stylesheet that imports them.