Advantages & Disadvantages of CSS

External Style Sheets

Advantages
Can control styles for multiple documents at once.
Classes can be created for use on multiple HTML element types in many documents.
Selector and grouping methods can be used to apply styles under complex contexts.

Disadvantages
An extra download is required to import style information for each document.
The rendering of the document may be delayed until the external style sheet is loaded.
Becomes slightly unwieldy for small quantities of style definitions.

Embedded Style Sheets

Advantages
Classes can be created for use on multiple tag types in the document.
Selector and grouping methods can be used to apply styles under complex contexts.
No additional downloads necessary to receive style information.

Disadvantage
This method can not control styles for multiple documents at once.

Inline Styles

Advantages
Useful for small quantities of style definitions.
Can override other style specification methods at the local level so only exceptions need to be listed in conjunction with other style methods.

Disadvantages
Does not distance style information from content (a main goal of SGML/HTML).
Can not control styles for multiple documents at once.
Author can not create or control classes of elements to control multiple element types within the document.
Selector grouping methods can not be used to create complex element addressing scenarios.