So we can make the code in every html document‘s head like that :
<head>
<title>This is my first page !</title>
<link rel = "stylesheet"
type = "text/css"
href = "styles.css"
/>
</head>
body{
background : green;
color: white;
}
a{
color: yellow;
}
the body means all page‘s body style, and the ‘a‘ means a tag get yellow color !
1. The threen groups :
1.1 Sans-serif: sans meands out !
:
1.2 Serif
1.3 Monos paced: Always use when u want show some code examples
原文：http://www.cnblogs.com/BJTUzhengli/p/5155255.html