See if this works...
Dump it in a html cell on a form....
If it does work you should then put the css out in an external file and then inlude linking it in
your startup.html file.
<style>
.btn {
background: #3498db;
background-image: -webkit-linear-gradient(top, #3498db, #2980b9);
background-image: -moz-linear-gradient(top, #3498db, #2980b9);
background-image: -ms-linear-gradient(top, #3498db, #2980b9);
background-image: -o-linear-gradient(top, #3498db, #2980b9);
background-image: linear-gradient(to bottom, #3498db, #2980b9);
-webkit-border-radius: 4;
-moz-border-radius: 4;
border-radius: 4px;
font-family: Arial;
color: #ffffff;
font-size: 20px;
padding: 10px 20px 10px 20px;
text-decoration: none;
}
.btn:hover {
background: #3cb0fd;
background-image: -webkit-linear-gradient(top, #3cb0fd, #3498db);
background-image: -moz-linear-gradient(top, #3cb0fd, #3498db);
background-image: -ms-linear-gradient(top, #3cb0fd, #3498db);
background-image: -o-linear-gradient(top, #3cb0fd, #3498db);
background-image: linear-gradient(to bottom, #3cb0fd, #3498db);
text-decoration: none;
}</style>
<a class="btn" href="mailto:<<RegularUser.email>>">Send Mail</a>