1312: Implement initial vocabulary browsing mechanism

Task-Url: https://pm.winseda.de/issues/1312

css/application-gs.css

@@ -392,6 +392,25 @@
       font-weight: bold;
       font-size: 125%; }
 
+.sidebar-filters h3 {
+  margin: 0; }
+.sidebar-filters ul {
+  margin: 0;
+  list-style: none;
+  padding-left: 0; }
+  .sidebar-filters ul li {
+    text-indent: -10px;
+    padding-left: 10px; }
+    .sidebar-filters ul li span {
+      font-size: 90%;
+      color: #494e7d;
+      cursor: pointer; }
+      .sidebar-filters ul li span:hover {
+        color: #2d304d; }
+.sidebar-filters button {
+  margin-top: 6px;
+  margin-bottom: 24px; }
+
 .slider {
   width: 95%; }
   .slider > .dragger {