Freedom

** Cross Browser Issue

Always set body margin and padding beforehand

body {

    margin: 0px;

    padding: 0px;

}

Don't missing the !DOCTYPE declaration at the beginning of the html file.

** Pseudo class

:link

:hover

:active

:visited

:first-child

:first-letter

:first-line

:focus

:before   => Insert content before every specified element

:after      => Insert content after every specified element

:lang

** a tag Pseudo class

a:link => unvisited link

a:active => selected link

** :first-class pseudo class

The :first-child pseudo-class matches a specified element that is the first child of another element.

selector:first-child { }

http://www.w3schools.com/css/tryit.asp?filename=trycss_first-child1

Match all the first selector2 which is in selector1 (the first children of selector1)

selector1 > selector2:first-child { }

http://www.w3schools.com/css/tryit.asp?filename=trycss_first-child2

MAth all selector2 of selector1 which is the first child of another element

http://www.w3schools.com/css/tryit.asp?filename=trycss_first-child3

** :lang psedo class

The :lang pseudo-class allows you to define special rules for different languages.

<style type="text/css">

    q:lang(no) {quotes: "~" "~";}

</style>

http://www.w3schools.com/css/tryit.asp?filename=trycss_lang