made colour better

src/components/root/Navigation.js

@@ -5,7 +5,7 @@ export class Navigation extends Component {
   render() {
     return (
       <nav>
-        <div className="navbar-fixed cyan darken-4">
+        <div className="navbar-fixed grey darken-1">
           <div className="nav-wrapper">
             <ul className="left hide-on-med-and-down">
               <li>