Set vim-hotkeys help panels to same height

searx/static/plugins/css/vim_hotkeys.css

     overflow-y: auto;
     max-height: 80%;
 }
+
+.dflex {
+    display: -webkit-box;  /* OLD - iOS 6-, Safari 3.1-6 */
+    display: -moz-box;     /* OLD - Firefox 19- (buggy but mostly works) */
+    display: -ms-flexbox;  /* TWEENER - IE 10 */
+    display: -webkit-flex; /* NEW - Chrome */
+    display: flex;         /* NEW, Spec - Opera 12.1, Firefox 20+ */
+}
+
+.iflex {
+    -webkit-box-flex: 1; /* OLD - iOS 6-, Safari 3.1-6 */
+    -moz-box-flex: 1;    /* OLD - Firefox 19- */
+    -webkit-flex: 1;     /* Chrome */
+    -ms-flex: 1;         /* IE 10 */
+    flex: 1;             /* NEW, Spec - Opera 12.1, Firefox 20+ */
+}

searx/static/plugins/js/vim_hotkeys.js

             var first = i % 2 === 0;
 
             if (first) {
-                html += '<div class="row">';
+                html += '<div class="row dflex">';
             }
-            html += '<div class="col-sm-' + (first && lastCategory ? 12 : 6) + '">';
+            html += '<div class="col-sm-' + (first && lastCategory ? 12 : 6) + ' dflex">';
 
-            html += '<div class="panel panel-default">';
+            html += '<div class="panel panel-default iflex">';
             html += '<div class="panel-heading">' + cat[0].cat + '</div>';
             html += '<div class="panel-body">';
             html += '<ul class="list-unstyled">';