W3C Candidate Recommendation, 19 May 2016. One of the fundamental design principles of CSS is cascading, which allows several style sheets to influence the presentation of a document. When different declarations try to set a value for the same element/property combination, the conflicts must somehow be resolved. The opposite problem arises when no declarations try to set a the value for an element/property combination. In this case, a value is be found by way of inheritance or by looking at the property’s initial value.