Question 11 :
Can CSS be used with other than HTML documents?
Yes. CSS can be used with any ny structured document format. e.g. XML, however, the method of linking CSS with other document types has not been decided yet.
Question 12 :
Can Style Sheets and HTML stylistic elements be used in the same document?
Yes. Style Sheets will be ignored in browsers without CSS-support and HTML stylistic elements used.
Question 13 :
Why use Style Sheets?
Style sheets allow a much greater degree of layout and display control than has ever been possible thus far in HTML. The amount of format coding necessary to control display characteristics can be greatly reduced through the use of external style sheets which can be used by a group of documents. Also, multiple style sheets can be integrated from different sources to form a cohesive tapestry of styles for a document. Style sheets are also backward compatible - They can be mixed with HTML styling elements and attributes so that older browsers can view content as intended.
Question 14 :
What does the "Cascading" in "Cascading Style Sheets" mean?
Style Sheets allow style information to be specified from many locations. Multiple (partial) external style sheets can be referenced to reduce redundancy, and both authors as well as readers can specify style preferences. In addition, three main methods can be employed by an author to add style information to HTML documents, and multiple approaches for style control are available in each of these methods. In the end, style can be specified for a single element using any, or all, of these methods. What style is to be used when there is a direct conflict between style specifications for an element?
Cascading comes to the rescue. A document can have styles specified using all of these methods, but all the information will be reduced to a single, cohesive "virtual" Style Sheet. Conflict resolution is based on each style rule having an assigned weight according to its importance in the scheme of things. A rule with a higher overall importance will carry a higher weight. This will be used in place of a competing style rule with a lower weight/importance. A hierarchy of competing styles is thus formed creating a "cascade" of styles according to their assigned weights. The algorithm used to determine this cascading weight scale is fairly complex.
Question 15 :
What is CSS rule 'at-rule'?
There are two types of CSS rules: ruleset and at-rule. At-rule is a rule that applies to the whole style sheet and not to a specific selector only (like in ruleset). They all begin with the @ symbol followed by a keyword made up of letters a-z, A-Z, digits 0-9, dashes and escaped characters, e.g. @import or @font-face.