<link href="style1.css" rel="stylesheet" type="text/css">
<link href="style2.css" rel="stylesheet" type="text/css">
1.document.getElementById - id selector
document.getElementsByName - name selector
document.getElementsByTagname - tag name selector
2.
{range selector} a { style... }
{another range selector} a { style... }
3.
put all css codes in outer css file so that u can easily maintain them
4.
<body style="text-align: center">
<div style="float: left"></div>
<div style="float: left"></div>
<!-- <div style="float: left"></div>-->
</body>
5.
{ overflow: auto} or { overflow: hidden }