First Webpage

I've done some HTML and CSS before, but never that much, especially not CSS. CSS makes managing styles much easier and I was suriprised to discover that you can put all the setting to different html files on one css file. Anyway, I still got a lot to learn, but this is what I have so far:

http://homepages.nyu.edu/~km602/CLab/main.htm

Here's the css file, the HTML files should be viewable, by "view source".

.bann {
font-family: Verdana, Arial, Helvetica, sans-serif;
font-size: 38px;
font-weight: bold;
background-image: none;
border: 50px groove #00FF99;
background-color: #2277FF;
color: #FFFFFF;
float: left;
text-align: center;
width: 90%;

}
.bod {
font-family: Arial, Helvetica, sans-serif;
font-size: 12px;
color: #FFFFFF;
background-image: url('Neuron.jpg');
height: 100%;
width: 100%;

}
.men {
font-family: "Courier New", Courier, mono;
background-color: #2277FF;
border: medium groove #00FF99;
text-align: center;
vertical-align: middle;
height: 100%;
}