only one element on a page can have a specific id attribute 

div#blah targets the div element with the id="blah" attribute

#blah targets the one element with the id="blah" attribute

any number of elements on a page can specify the same class attribute 

div.flibberty targets the div element(s) that contain the class="flibberty" attribute

.flibberty targes any element(s) that contain the class="flibberty" attribute

 
Read more about CSS and specificity:  CSS Specificity for Poker Players

 
PS: I don't play cards (anymore)

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Sincerely,

Carl
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vine type - content management with standards in mind - vinetype.com
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