Upgrade to bootstrap v4-beta.

package.json

@@ -51,7 +51,7 @@
     "@types/node": "^8.0.20",
     "angular2-text-mask": "^8.0.3",
     "base64util": "^1.0.2",
-    "bootstrap": "^3.3.7",
+    "bootstrap": "4.0.0-beta",
     "c3": "^0.4.15",
     "font-awesome": "^4.7.0",
     "jquery": "^3.2.1",

src/app.component.ts

@@ -6,7 +6,7 @@ import { Component } from '@angular/core';
   selector: 'accountant',
   template: `
     <!-- Navbar -->
-    <nav class="navbar fixed-top navbar-inverse bg-inverse">
+    <nav class="navbar fixed-top navbar-dark bg-dark">
       <a class="navbar-brand" routerLink="/accounts">&nbsp;Accountant</a>
     </nav>