As my colleague Ryan mentioned, you can use CSS to customize the look of just about any element on your site. You can add that CSS code to the bottom of your theme stylesheet, or to the custom CSS editor available under Appearance > Edit CSS in your dashboard.
Here is an example of a few things I changed on your site. Here is the end result:
http://i.wpne.ws/eDKF
And here is the CSS:
.jetpack_subscription_widget {
text-align: center;
border-color: #7c7c82;
border-top-left-radius: 4px;
border-top-right-radius: 4px;
border-bottom-left-radius: 4px;
border-bottom-right-radius: 4px;
border-style: solid;
border-width: 2px;
background: rgba(84, 91, 143, 1);
-pie-background: linear-gradient(rgba(84, 91, 143, 1) 45%, rgba(8, 16, 53, 1));
background: -webkit-gradient(linear, left top, left bottom, color-stop(45%, rgba(84, 91, 143, 1)), color-stop(1, rgba(8, 16, 53, 1)));
background: -moz-linear-gradient(rgba(84, 91, 143, 1) 45%, rgba(8, 16, 53, 1));
background: -o-linear-gradient(rgba(84, 91, 143, 1) 45%, rgba(8, 16, 53, 1));
background: linear-gradient(rgba(84, 91, 143, 1) 45%, rgba(8, 16, 53, 1));
-webkit-box-shadow: 0px 0px 2px #807c80;
-moz-box-shadow: 0px 0px 2px #807c80;
box-shadow: 0px 0px 2px #807c80;
padding-top: 20px;
}
.jetpack_subscription_widget #subscribe-email {
padding-left: 50px;
width: 60%;
display: inline-block;
}
.jetpack_subscription_widget #subscribe-submit {
padding-right: 50px;
width: 20%;
display: inline-block;
}
.jetpack_subscription_widget #subscribe-email input[type="email"] {
height: 25px;
float: left;
padding-left: 5px;
}
.jetpack_subscription_widget #subscribe-submit input[type="submit"] {
float: left;
border-top-left-radius: 4px;
border-top-right-radius: 4px;
border-bottom-left-radius: 4px;
border-bottom-right-radius: 4px;
}
I followed the style of the button appearing under the form, and added some extra styling to it. Feel free to play with the different values to tweak the form even more!
