now using SCSS for better theming support

src-ui/src/app/components/app-frame/app-frame.component.scss

@@ -0,0 +1,84 @@
+
+  /*
+ * Sidebar
+ */
+
+ .sidebar {
+  position: fixed;
+  top: 0;
+  bottom: 0;
+  left: 0;
+  z-index: 100; /* Behind the navbar */
+  padding: 48px 0 0; /* Height of navbar */
+  box-shadow: inset -1px 0 0 rgba(0, 0, 0, .1);
+}
+
+@media (max-width: 767.98px) {
+  .sidebar {
+    top: 5rem;
+  }
+}
+
+.sidebar-sticky {
+  position: relative;
+  top: 0;
+  height: calc(100vh - 48px);
+  padding-top: .5rem;
+  overflow-x: hidden;
+  overflow-y: auto; /* Scrollable contents if viewport is shorter than content. */
+}
+
+@supports ((position: -webkit-sticky) or (position: sticky)) {
+  .sidebar-sticky {
+    position: -webkit-sticky;
+    position: sticky;
+  }
+}
+
+.sidebar .nav-link {
+  font-weight: 500;
+  color: #333;
+}
+
+.sidebar .nav-link .sidebaricon {
+  margin-right: 4px;
+  color: #999;
+}
+
+.sidebar .nav-link.active {
+  color: #007bff;
+}
+
+.sidebar .nav-link:hover .sidebaricon,
+.sidebar .nav-link.active .sidebaricon {
+  color: inherit;
+}
+
+.sidebar-heading {
+  font-size: .75rem;
+  text-transform: uppercase;
+}
+
+
+/*
+ * Navbar
+ */
+
+ .navbar-brand {
+  padding-top: .75rem;
+  padding-bottom: .75rem;
+  font-size: 1rem;
+  background-color: rgba(0, 0, 0, .25);
+  box-shadow: inset -1px 0 0 rgba(0, 0, 0, .25);
+}
+
+.navbar .navbar-toggler {
+  top: .25rem;
+  right: 1rem;
+}
+
+.navbar .form-control {
+  padding: .75rem 1rem;
+  border-width: 0;
+  border-radius: 0;
+}