As far as I know there is no:
border-bottom-margin
property. From testing here, it looks like the height declaration is being ignored by IE and is the problem in FF:
Code:
h1 {
font-family: times new roman;
font-size: 13px;
color: #5F7C78;
text-align: left;
letter-spacing: 1px; height: 4px;
text-transform: uppercase;
font-weight: bold;
border-bottom: 1px solid #5F7C78;
margin: 2px;
}
4px is much too short for such an element anyway. Just get rid of it altogether. If that causes some odd problem in IE, make it an IE only declaration but, I doubt that will be needed.
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