This page demonstrates some simple CSS cascading. Style properties for the different tags in this page are read from various places:
Here is a second paragraph. It reads its style properties from two different places: "defaults.css" and "additions.css". From the first sheet ("defaults.css") this paragraph gets its margins and font. From the second sheet ("additions.css") comes this green colour.
Above is again a header tag (h1), like there was one in the first page. In this case it first reads its font properties from the "defaults.css". In addition, the header is now horizontally centered, because this header tag has an id attribute with value "centered" and the "additions.css" contains corresponding ID selector "#centered" defining an CSS2 property "text-align" with value "center".
By default, the page background would be black colored, as defined in "defaults.css". This page, however, contains an embedded stylesheet in the style-element, and there the background color of the body is overridden with an background-image. Thus an MPEG I-frame image is shown in the page background instead of the default black color.