Clip borders/ rounded corner of webpage like twitter?

Question

I want to build a webpage like twitter or microsoft hohm. Like clipping borders, buttons, clipped text box. How can I do this in Dreamweaver? Is these things are done by photoshop? Any tutorial or links will be very helpful. If there are any webdesign template of twitter of something like twitter please let me know.

Answer 1

Its done by CSS.

<div id="wrapper">
...
</div>

<style type="text/css">
#wrapper{
      width:800px;
      margin:0 auto;
}
</style>