diff --git a/Arduino/CanGrow/include/Webserver/Page_system.h b/Arduino/CanGrow/include/Webserver/Page_system.h
index 94edb1c..1cdaa63 100644
--- a/Arduino/CanGrow/include/Webserver/Page_system.h
+++ b/Arduino/CanGrow/include/Webserver/Page_system.h
@@ -30,17 +30,56 @@
 
 #include "Page_system_HTML.h"
 
+/* subnav processor */
+
+bool Test_WebPage_system_SUBNAV(const String& var) {
+  if(
+    (var == "SUBNAV") ||
+    (var == "ACTIVE_SUBNAV_OUTPUT") ||
+    (var == "ACTIVE_SUBNAV_UPDATE") ||
+    (var == "ACTIVE_SUBNAV_RESTART") ||
+    (var == "ACTIVE_SUBNAV_WIPE")) {
+    return true;
+  } else {
+    return false;
+  }
+}
+
+/*
+ * Proc_WebPage_system_SUBNAV - subnav processor for system
+ * this function works as same as AddHeaderFooter from Common.h
+ * byte activeSubnav:
+ *   1 - Output
+ *   2 - Update
+ *   3 - Restart
+ *   4 - Wipe
+ */
+String Proc_WebPage_system_SUBNAV(const String& var, byte activeSubnav = 0) {
+  String activeSubnav_ClassName = "activeNav";
+  if(var == "SUBNAV") {
+    return String(Page_system_HTML_SUBNAV);
+  } else if((var == "ACTIVE_SUBNAV_OUTPUT") && (activeSubnav == 1)) {
+    return activeSubnav_ClassName;
+  } else if((var == "ACTIVE_SUBNAV_UPDATE") && (activeSubnav == 2)) {
+    return activeSubnav_ClassName;
+  } else if((var == "ACTIVE_SUBNAV_RESTART") && (activeSubnav == 3)) {
+    return activeSubnav_ClassName;
+  } else if((var == "ACTIVE_SUBNAV_WIPE") && (activeSubnav == 4)) {
+    return activeSubnav_ClassName;
+  } else {
+    return String();
+  }
+}
+
 /*
  * Main system page
  */
-
-
 // https://techtutorialsx.com/2018/07/23/esp32-arduino-http-server-template-processing-with-multiple-placeholders/
 String Proc_WebPage_system(const String& var) {
   if(TestHeaderFooter(var)) {
     return AddHeaderFooter(var, 2);
-  } else if(var == "SUBNAV") {
-    return String(Page_system_HTML_SUBNAV);
+  } else if(Test_WebPage_system_SUBNAV(var)) {
+    return Proc_WebPage_system_SUBNAV(var);
   } else {
     return String();
   }
@@ -100,8 +139,8 @@ void WebPage_system(AsyncWebServerRequest *request) {
 String Proc_WebPage_system_restart(const String& var) {
   if(TestHeaderFooter(var)) {
     return AddHeaderFooter(var, 2);
-  } else if(var == "SUBNAV") {
-    return String(Page_system_HTML_SUBNAV);
+  } else if(Test_WebPage_system_SUBNAV(var)) {
+    return Proc_WebPage_system_SUBNAV(var, 3);
   } else if(var == "RESTART_MSG") {
     return String(Page_system_restart_HTML_RESTART_MSG);
   } else {
@@ -174,8 +213,8 @@ void WebPage_system_update_ApplyUpdate(AsyncWebServerRequest *request, String fi
 String Proc_WebPage_system_update(const String& var) {
   if(TestHeaderFooter(var)) {
     return AddHeaderFooter(var, 2);
-  } else if(var == "SUBNAV") {
-    return String(Page_system_HTML_SUBNAV);
+  } else if(Test_WebPage_system_SUBNAV(var)) {
+    return Proc_WebPage_system_SUBNAV(var, 2);
   } else {
     return String();
   }
@@ -213,9 +252,9 @@ void WebPage_system_update(AsyncWebServerRequest *request) {
  */
 String Proc_WebPage_system_wipe(const String& var) {
   if(TestHeaderFooter(var)) {
-    return AddHeaderFooter(var);
-  } else if(var == "SUBNAV") {
-    return String(Page_system_HTML_SUBNAV);
+    return AddHeaderFooter(var, 2);
+  } else if(Test_WebPage_system_SUBNAV(var)) {
+    return Proc_WebPage_system_SUBNAV(var, 4);
   } else if(var == "WIPE_MSG") {
     return String(Page_system_wipe_HTML_WIPE_MSG);
   } else {
@@ -254,9 +293,9 @@ void WebPage_system_wipe(AsyncWebServerRequest *request) {
  */
 String Proc_WebPage_system_output(const String& var) {
   if(TestHeaderFooter(var)) {
-    return AddHeaderFooter(var);
-  } else if(var == "SUBNAV") {
-    return String(Page_system_HTML_SUBNAV);
+    return AddHeaderFooter(var, 2);
+  } else if(Test_WebPage_system_SUBNAV(var)) {
+    return Proc_WebPage_system_SUBNAV(var, 1);
   } else{
     return String();
   }
diff --git a/Arduino/CanGrow/include/Webserver/Page_system_HTML.h b/Arduino/CanGrow/include/Webserver/Page_system_HTML.h
index f7bb52b..69601e2 100644
--- a/Arduino/CanGrow/include/Webserver/Page_system_HTML.h
+++ b/Arduino/CanGrow/include/Webserver/Page_system_HTML.h
@@ -55,10 +55,10 @@ const char* Page_system_HTML PROGMEM = R"(%HEADER%
 %FOOTER%)";
 
 const char* Page_system_HTML_SUBNAV PROGMEM = R"(<ul class='subnav'>
-  <li><a  href='/system/output'>&#9889; Output configuration</a></li>
-  <li><a  href='/system/update'>&#x1F504; Firmware update</a></li>
-  <li><a href='/system/restart' >&#x1F501; CanGrow restart</a></li>
-  <li><a href='/system/wipe' >&#x1F4A3; Factory reset</a></li>
+  <li><a class='%ACTIVE_SUBNAV_OUTPUT%' href='/system/output'>&#9889; Output configuration</a></li>
+  <li><a class='%ACTIVE_SUBNAV_UPDATE%' href='/system/update'>&#x1F504; Firmware update</a></li>
+  <li><a class='%ACTIVE_SUBNAV_RESTART%' href='/system/restart' >&#x1F501; CanGrow restart</a></li>
+  <li><a class='%ACTIVE_SUBNAV_WIPE%' href='/system/wipe' >&#x1F4A3; Factory reset</a></li>
 </ul>)";
 
 /*