Menu: Do not show outline upon focus

public/css/icinga/layout.less

@@ -53,6 +53,12 @@
   background-size: contain;
   display: block;
   height: 100%;
+  width: 100%;
+
+  &:focus {
+    outline: none;
+    opacity: .6;
+  }
 }
 
 #icinga-logo {

public/css/icinga/menu.less

@@ -24,7 +24,7 @@
   > a {
     &:focus {
       color: @icinga-blue;
-      outline: -3px;
+      outline: none;
     }
 
     &:hover {
@@ -319,7 +319,11 @@ input[type=text].search-input {
     width: 2em;
   }
 
-  &:hover {
+  &:focus {
+    outline: none;
+  }
+
+  &:hover, &:focus {
     i {
       color: @icinga-blue;
     }