title: Bootstrap navbar has bottom margin. Why?
body: <p>What is the purpose of having a <code>margin-bottom: 20px;</code> on the <code>.navbar</code> class? I'm not asking how to get rid of it (that's simple, just do <code>.navbar {margin-bottom: 0px;}</code>, but I'm wondering what the design purpose is. It must be useful somewhere, when interacting with other aspects of boostrap. does anyone know?</p>