Update navigation: new menu, active page highlight, centered navbar without logo

layouts/partials/slideout.html

@@ -0,0 +1,16 @@
+<div id="mobile-navbar" class="mobile-navbar">
+  <div class="mobile-navbar-icon">
+    <span></span>
+    <span></span>
+    <span></span>
+  </div>
+</div>
+<nav id="mobile-menu" class="mobile-menu slideout-menu">
+  <ul class="mobile-menu-list">
+    {{ range .Site.Menus.main -}}
+      <a href="{{ .URL | safeURL }}">
+        <li class="mobile-menu-item">{{ .Name }}</li>
+      </a>
+    {{- end }}
+  </ul>
+</nav>