无图片作的css圆角

<STYLE type=text/css>
body{padding: 20px;background-color: #FFF;
    font: 100.01% "Trebuchet MS",Verdana,Arial,sans-serif}
h1,h2,p{margin: 0 10px}
h1{font-size: 250%;color: #FFF}
h2{font-size: 200%;color: #f0f0f0}
p{padding-bottom:1em}
h2{padding-top: 0.3em}
div#nifty{ margin: 0 10%;background: #9BD1FA}

b.rtop, b.rbottom{display:block;background: #FFF}
b.rtop b, b.rbottom b{display:block;height: 1px;
    overflow: hidden; background: #9BD1FA}
b.r1{margin: 0 5px}
b.r2{margin: 0 3px}
b.r3{margin: 0 2px}
b.rtop b.r4, b.rbottom b.r4{margin: 0 1px;height: 2px}
</STYLE>
<DIV id=nifty><B class=rtop><B class=r1></B><B class=r2></B><B class=r3></B><B class=r4></B></B>
<H1>Nifty Corners</H1>
<P>Auiiui uieiouo auuaa oiaue uaou iioiiou uiio a io ieeoai uaouoe uoiaau eeauauou u oiauuie eo ui.</P>
<H2>Rounded corners without images</H2>
<P>Aaeao aiieuouiu io ueuiieu uei oeio uooiau uue ooiea ooiaui eue ouue i uiaoo iouieiuia uueeo ieieuiiau ueaooa iou iaeieuo uoao iauoi u i oeioooe auo a ooe u uuuo oaooaae uoa iuiuiaeu iioaeu uuiu eeu ea eouoiuo ua o.</P>
<P>Iiuiuaea ouea ieuuio o i iuo oiei uoeeou ieoau uaeeiu uouooa uiaiaue ii oo iei eiaiueoo iaoa euiaou uoia uuei ua aoauia ieoae eioiaia eu uiueeiui ueuaiuo uaa eie oaeee uau ooieoi uoii oeuioei uouiiuu ioeiuoe eaeuoi.</P>
<P>Iueuouii eei iueoie i iooououe eoio eeeuoeio u eu ee uueeo eiuoi iooeiu uuiei uiaeo oaaoo iuu uuue auo au o ooueooii oueui aeeeau uoeoeee aeuaea aoeuoieeo aio aaiio iuouau e aouueuuie oiieae eioii oeeiu uaeuueuu eeue ieu.</P><B class=rbottom><B class=r4></B><B class=r3></B><B class=r2></B><B class=r1></B></B></DIV>