body,div,dl,dt,dd,ul,ol,li,h1,h2,h3,h4,h5,h6,pre,form,fieldset,input,textarea,p,
blockquote,th,td {margin:0; padding:0; }
table { border-collapse:collapse; border-spacing:0; }
fieldset,img { border:0; }
address,caption,cite,code,dfn,em,strong,th,var { font-style:normal; font-weight:normal; }
ol,ul { list-style:none; }
caption,th { text-align:left; }
h1,h2,h3,h4,h5,h6 { font-size:100%; font-weight:normal; }
q:before,q:after { content:”; }
abbr,acronym { border:0; }

其次，我們重設(shè)瀏覽器字體的大小為10像素，使用如下： 

html {font-size: 62.5%;}

這個大小基本合適，然后您可以根據(jù)自己的需要調(diào)整大小，如 標題1為120像素: 

h1 {font-size: 2em;}

div#container {margin: 0 auto;}

<div id='parent'>
<div id='son'></div>
</div>

div.popup { height:400px; width:500px; position: absolute; top: 50%; left: 50%;}
div.popup { margin-top: -200px; margin-left: -250px;}

.left {float: left;}
.right {float: right;}
img .left { border:2px solid #aaaaaa; margin: 0 10px 0 0;}
img .right { border:2px solid #aaaaaa; margin: 0 0 0 10px; padding: 1px;}

div {float:left;margin:40px;display:inline;}