The document body style affects the entire web page document by controlling much of its overall appearance. Most other styles inherit the font attributes from the document body style, unless you customize those styles. Setting the font family and font size for the document body style means that all new and existing web pages linked to this style sheet use the specified font. Other document body attributes include setting the background color for the entire web page. Furthermore, the options in the Spacing dialog box control the page margins. The Before and After fields control the top and bottom margins of the page, while the Indentation Left and Indentation Right fields apply indents that affect the paragraph style and all other paragraph-based styles such as headings, bullet lists, numbered lists, and so on.
The default alignment for the document body style is left aligned, but you can select another alignment such as Align Justify. Note that the selected alignment applies to all web pages linked to the style sheet. Formatting that centers or right aligns text is probably better suited to paragraph styles.
Note: Since there can be only one document body style in a style sheet, the Make Default option is not available for this style.