Cascading style sheets is the term for HTML styles developed by the World Wide Web Consortium (W3C). "Cascading" refers to the hierarchy of the three styles (external style sheets, embedded, and inline), when they are used in combination.
A single block of text can be formatted to use all three styles; therefore, one style must have priority over the others so Help authors can control the formatting in their topics.
For example, a style sheet is linked to a topic. It includes formats for the style "Heading 2," and a paragraph uses this style. The topic also has an embedded style created for "Heading 2," where the formatting is slightly different from the attributes used in the style sheet. The paragraph will use the formatting of the embedded style over the external style sheet.
If the paragraph (or parts of the text in the paragraph) are formatted even more by applying inline styles (applied from the Format menu in the WYSIWYG Editor), the block of text will use the formatting of the inline style over the embedded style.
The hierarchy of inline, embedded, and external styles is known as "cascading," as illustrated in the examples below.
The topic is linked to an external style sheet. The style "Normal" is applied to a paragraph. It looks like this:
The island's newest resort is opening in January 2001. Set on 20 acres of lushly landscaped grounds, Mirror Sands features tropical garden-style villas in a tranquil setting.
The author creates an embedded style for "Normal" which uses a different font and font size from the one created in the style sheet. The paragraph takes on the attributes of the embedded style. It looks like this:
The island's newest resort is opening in January 2001. Set on 20 acres of lushly landscaped grounds, Mirror Sands features tropical garden-style villas in a tranquil setting.
The author formats a block of text in the paragraph so the text uses different font attributes. This is an inline style that formats the selected block of text in the paragraph. It looks like this:
The island's newest resort is opening in January 2001. Set on 20 acres of lushly landscaped grounds, Mirror Sands features tropical garden-style villas in a tranquil setting.
Note: For more information about the origins and details of cascading style sheets, visit the World Wide Web Consortium (W3C).