= CSS declaration
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A <CSS declaration> associates a <CSS property> with a <CSS property value>, optionally marked important. In source syntax, a colon separates the name from the value, and semicolons separate declarations in a list. For example, `color: red` declares a foreground color; the surrounding <CSS selector> determines which elements the rule addresses.<CSS Syntax Module Level 3 by World Wide Web Consortium>[Syntax Description; declaration definition: name, component-value list and important flag]{ref}
The rule `p { color: red; width: 20px; }` contains two <CSS declarations>. The braces enclose the block of <CSS declarations>. `!important` in `color: red !important` sets the declaration's priority flag; it is not part of the color value used to paint the text.
Parsing a declaration is only one stage of validation. `width: blue` has the superficial name-colon-value form, but blue is not a valid width value, so it does not supply a usable width declaration. An unrecognized property name is likewise not a way to create an arbitrary new built-in styling property. A preceding valid declaration can remain effective when a later invalid one is discarded.<CSS Syntax Module Level 3 by World Wide Web Consortium>[Error Handling and parsing declarations; distinction between generic syntax and property-specific interpretation]{ref}
When several valid declarations address the same element and property, the <CSS cascade> decides among them. For ordinary declarations with equal prior cascade priorities and equal <CSS specificity>, a later declaration wins. The declaration expresses a candidate value; its presence in a file alone does not prove that the candidate becomes the element's final presentation.
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