greadient button over effect

.grad_button  {
color: #000; width: 145px; height: 30px;
border: solid 1px #999; text-align:center; padding: 5px 0px 0px 0px; margin: 10px 0px 0px 160px; cursor: pointer; font-family:Arial, Helvetica, sans-serif; font-size: 16px; text-decoration:none; font-weight:bold;
background: #f78d1d;
background: -webkit-gradient(linear, left top, left bottom, from(#f1f1f1), to(#dfdfdf));
background: -moz-linear-gradient(top, #f1f1f1, #dfdfdf);
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#f1f1f1', endColorstr='#dfdfdf');
}
.grad_button  a {
color: #fef4e9; width: 145px; height: 30px;
border: solid 1px #999; text-align:center; padding: 5px 0px 0px 0px; cursor: pointer; text-decoration:none;
background: #f78d1d;
background: -webkit-gradient(linear, left top, left bottom, from(#f1f1f1), to(#dfdfdf));
background: -moz-linear-gradient(top, #f1f1f1, #dfdfdf);
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#f1f1f1', endColorstr='#dfdfdf');
}
.grad_button:hover {
background: #f47c20; color: #fff;
background: -webkit-gradient(linear, left top, left bottom, from(#59cbe5), to(#3ab3d1));
background: -moz-linear-gradient(top, #59cbe5, #3ab3d1);
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#59cbe5', endColorstr='#3ab3d1');
}