border-width:10px
border-top-width:10px
border-right-width:10px
border-bottom-width:10px
border-left-width:10px
border-top-width:5px;
border-right-width:1px;
border-bottom-width:2px;
border-left-width:8px
<html>
<head>
<META http-equiv="Content-Type" content="text/html; charset=Shift_JIS">
<META http-equiv="Content-Style-Type" content="text/css">
<title>枠線で囲まれたテキスト（太さ）</title>
<style type="text/css">
<!--
p { border-style:solid;
padding:5px;
border-color:red;}
.sample1 { border-width:10px;}
.sample2 { border-top-width:10px;}
.sample3 { border-right-width:10px;}
.sample4 { border-bottom-width:10px;}
.sample5 { border-left-width:10px;}
.sample6 { border-top-width:5px;
border-right-width:1px;
border-bottom-width:2px;
border-left-width:8px;}
-->
</style>
</head>
<body bgcolor="#FFFFFF">
<p class="sample1">border-width:10px</p>
<p class="sample2">border-top-width:10px</p>
<p class="sample3">border-right-width:10px</p>
<p class="sample4">border-bottom-width:10px</p>
<p class="sample5">border-left-width:10px</p>
<p class="sample6">border-top-width:5px;<br>
border-right-width:1px;<br>
border-bottom-width:2px;<br>
border-left-width:8px</p>
</body>
</html>