View source for Template:Fieldset.css

.fieldset {
border: 1px solid black;
border-top: none;
padding: 0.5em;
margin: 1em 2px;
} .fieldset>.legend {
font: 1em normal;
margin: -1em -0.5em 0;
border-bottom: none; /* stfu mediawiki */
} .fieldset>.legend>span {
float: left; /* text in legend divs must be wrapped with span tags or it will BREAK! */
} .fieldset>.legend:before {
border-top: 1px solid black;
content: ' ';
float: left;
margin: 0.5em 2px 0 -1px;
width: 0.75em;
} .fieldset>.legend:after {
border-top: 1px solid black;
content: ' ';
display: block;
height: 1.5em;
left: 2px;
margin: 0 1px 0 0;
overflow: hidden;
position: relative;
top: 0.5em;
}