Exemplo do arquivo de estilos

*body {
margin:0;
padding:0;
}

#principal {
width:900px;
height:auto;
margin-top:30px;
margin-left:auto;
margin-right:auto;
}

#topo {
background-image:url(../Imagens/topo1.jpg);
width:100%;
height:105px;
background-repeat:no-repeat;
}

#home {
background-image:url(../Imagens/Home1.jpg);
width:100%;
height:310px;
margin-top:200px;
margin-left:auto;
margin-right:auto;
background-repeat:no-repeat;
}

#separador {
height:5px;
}

#corpo {
width:100%;
height:auto;
font-family:Verdana, Arial, Helvetica, sans-serif;
font-size:12px;
font-weight:bold;
text-align:left;
}

#entrar {
width:100%;
height:50px;
color:#000000;
font-family:"Berlin Sans FB Demi";
font-size:40px;
text-decoration:none;
}

#entrar a:link, a:visited{
color:#000000;
text-decoration:none;
}

#entrar a:hover{
background:#000000;
color:#FFFFFF;
}

#menu {
background-image:url(../Imagens/menu.jpg);
background-repeat:no-repeat;
width:100%;
height:61px;
padding:10px 0px 0px 20px;
}

#menu a{
font-family:Verdana, Arial, Helvetica, sans-serif;
font-size:13px;
font-weight:bold;
color:#000000;
word-spacing:5px;
text-decoration:none;
text-transform:uppercase;
}

#menu a:hover{
color:#99FF00;
}

#cadastro{
width:100%;
height:auto;
}

#cadastro form{
width:90%;
height:auto;
margin-left:auto;
margin-right:auto;
}

#cadastro fieldset{
border:1px #009900 solid;
padding:0 15px 10px 15px;
border-radius: 4px;
}

#cadastro legend{
color:#009900;
font-family:Verdana, Arial, Helvetica, sans-serif;
font-size:18px;
font-weight:bold;
padding:10px 0;
}

#cadastro label{
padding:3px 0;
}

#cadastro span{
color:#009900;
font-family:Verdana, Arial, Helvetica, sans-serif;
font-weight:bold;
font-size:12;
}

#cadastro input, select {
    font-size: 12px;
    font-family: Arial, Helvetica, sans-serif;
    font-weight:bold;
    padding: 4px;
    border: 0;
    color: #000033;
    background: url(../Imagens/input1.jpg) repeat-x center;
    box-shadow: 0 0 6px 2px #009900 inset;
    border-radius: 4px;
}
#cadastro input:focus, input:hover {
    box-shadow: 0 0 1px 1px #6CA6CD, 0 0 3px 3px #4A708B, 0 0 6px 2px #009900 inset;
}

#cadastro .send{
width:100px;
margin:10px auto;
cursor:pointer;
border:0;
}

#cadastro textarea {
    width: 750px;
    display:block;
    font-size: 12px;
    font-family: Arial, Helvetica, sans-serif;
    font-weight:bold;
    padding: 4px;
    border: 0;
    color: #000033;
    box-shadow: 0 0 6px 2px #009900 inset;
    border-radius: 4px;
}

.enviar {
width:80px;
margin:10px auto;
cursor:pointer;
font-weight:bold;
border:0;
background-color:#009900;
color:#FFFFFF;
}