Generates a 1-em margin above the text it encloses, increases the left and right margins on that block of text by one standard paragraph indent, and generates a 1-em margin below the enclosed text. 

Note: 1 em is smaller than a line-space, because it excludes any external leading.


Provides an element with a unique name within a single document. This is especially useful in works with extensive cross-referencing and linking, such as dictionaries, encyclopedias, or travel guides. Use of ids  simplifies linking and updates.
Affiliates an element with one or more classes.
Attaches a list of inline (name:value paired) CSS properties to a specific tag, for example: style="name:value;name:value"
Note: Media types other than "text/x-oeb1-css" will be ignored with a warning in a document of type "text/x-oeb1-document".
This attribute is ignored.