Example CSS code, add to your skin/reboot/css/themes/xx.css file...
Code:
.panel-default > .panel-heading { background: #1e88e5; color: #fff; border-bottom: none; }
.panel-default > .panel-heading h2 { font-size: 24px; }
.panel-body:not(.panel-product) { border: 1px solid #1e88e5; background: #e3f2fd; }
It's a good idea to use
Firebug, which helps you find CSS codes easier.
You can enable a Google font for menus/dialogs in the template settings.