<style type="text/css">
.mystyle1 {
border-width: thin;
border-style: solid;
border-color: black;
width: 20em;
padding: .5em;
margin: .5em;
text-align: center;
font-size: large;
font-weight: bold }

.mystyle2 {
border-width: medium;
border-style: solid;
border-color: black;
width: 20em;
padding: .5em;
margin: .5em;
text-align: center;
font-size: large;
font-weight: bold }

.mystyle3 {
border-width: thick;
border-style: solid;
border-color: black;
width: 20em;
padding: .5em;
margin: .5em;
text-align: center;
font-size: large;
font-weight: bold }

.mystyle4 {
border-width: .5ex;
border-style: solid;
border-color: black;
width: 20em;
padding: .5em;
margin: .5em;
text-align: center;
font-size: large;
font-weight: bold }
</style>
.....
<div class="mystyle1">A thin border around this text</div>
<div class="mystyle2">A medium border around this text</div>
<div class="mystyle3">A thick border around this text</div>
<div class="mystyle4">A .5ex border around this text</div>

....