Update CSS style used for the navigation

refs #5600

library/Icinga/Web/Navigation/Renderer/NavigationRenderer.php

@@ -304,10 +304,7 @@ class NavigationRenderer implements RecursiveIterator, NavigationRendererInterfa
      */
     public function beginItemMarkup(NavigationItem $item)
     {
-        $cssClass = array();
+        $cssClass = array(static::CSS_CLASS_ITEM);
-        if ($item->getActive()) {
-            $cssClass[] = static::CSS_CLASS_ACTIVE;
-        }
 
         if ($item->hasChildren() && $item->getChildren()->getLayout() === Navigation::LAYOUT_DROPDOWN) {
             $cssClass[] = static::CSS_CLASS_DROPDOWN;
@@ -317,16 +314,15 @@ class NavigationRenderer implements RecursiveIterator, NavigationRendererInterfa
                 ->setUrl('#');
         }
 
-        if (! empty($cssClass)) {
+        if ($item->getActive()) {
+            $cssClass[] = static::CSS_CLASS_ACTIVE;
+        }
+
         $content = sprintf(
             '<li id="%s" class="%s">',
             $this->view()->escape($item->getUniqueName()),
             join(' ', $cssClass)
         );
-        } else {
-            $content = '<li id="' . $this->view()->escape($item->getUniqueName()) . '">';
-        }
-
         return $content;
     }
 

library/Icinga/Web/Navigation/Renderer/NavigationRendererInterface.php

@@ -8,6 +8,13 @@ namespace Icinga\Web\Navigation\Renderer;
  */
 interface NavigationRendererInterface
 {
+    /**
+     * CSS class for items
+     *
+     * @var string
+     */
+    const CSS_CLASS_ITEM = 'nav-item';
+
     /**
      * CSS class for active items
      *
@@ -20,10 +27,12 @@ interface NavigationRendererInterface
      *
      * @var string
      */
-    const CSS_CLASS_DROPDOWN = 'dropdown';
+    const CSS_CLASS_DROPDOWN = 'dropdown-nav-item';
 
     /**
      * CSS class for a dropdown item's trigger
+     *
+     * @var string
      */
     const CSS_CLASS_DROPDOWN_TOGGLE = 'dropdown-toggle';
 
@@ -39,14 +48,14 @@ interface NavigationRendererInterface
      *
      * @var string
      */
-    const CSS_CLASS_NAV_DROPDOWN = 'dropdown-menu';
+    const CSS_CLASS_NAV_DROPDOWN = 'dropdown-nav';
 
     /**
      * CSS class for the ul element with tabs layout
      *
      * @var string
      */
-    const CSS_CLASS_NAV_TABS = 'nav-tabs';
+    const CSS_CLASS_NAV_TABS = 'tab-nav';
 
     /**
      * Icon for a dropdown item's trigger