update

src/gnome-shell/sass/widgets/_panel.scss

@@ -96,7 +96,7 @@ $panel_transition_duration: 250ms; // same as the overview transition duration
     // status area icons
     .system-status-icon {
       icon-size: 16px;
-      padding: 6px;
+      padding: $container_padding * 1.5;
       margin: 0 3px;
     }
 
@@ -108,9 +108,10 @@ $panel_transition_duration: 250ms; // same as the overview transition duration
       margin: 0;
     }
 
-    // .panel-status-indicators-box .system-status-icon {
-    //   margin: 0 3px;
-    // }
+    .panel-status-indicators-box .system-status-icon {
+      margin: 0 !important;
+      padding: $container_padding !important;
+    }
 
     .appindicator-trayicons-box {
       margin: 0 6px;

src/gnome-shell/shell-40-0/gnome-shell-Compact.css

@@ -1986,6 +1986,11 @@ StScrollBar StButton#vhandle:active, StScrollBar StButton#hhandle:active {
   margin: 0;
 }
 
+#panel .panel-button .panel-status-indicators-box .system-status-icon {
+  margin: 0 !important;
+  padding: 4px !important;
+}
+
 #panel .panel-button .appindicator-trayicons-box {
   margin: 0 6px;
 }

src/gnome-shell/shell-40-0/gnome-shell-Dark-Compact.css

@@ -1986,6 +1986,11 @@ StScrollBar StButton#vhandle:active, StScrollBar StButton#hhandle:active {
   margin: 0;
 }
 
+#panel .panel-button .panel-status-indicators-box .system-status-icon {
+  margin: 0 !important;
+  padding: 4px !important;
+}
+
 #panel .panel-button .appindicator-trayicons-box {
   margin: 0 6px;
 }

src/gnome-shell/shell-40-0/gnome-shell-Dark.css

@@ -1974,7 +1974,7 @@ StScrollBar StButton#vhandle:active, StScrollBar StButton#hhandle:active {
 
 #panel .panel-button .system-status-icon {
   icon-size: 16px;
-  padding: 6px;
+  padding: 9px;
   margin: 0 3px;
 }
 
@@ -1986,6 +1986,11 @@ StScrollBar StButton#vhandle:active, StScrollBar StButton#hhandle:active {
   margin: 0;
 }
 
+#panel .panel-button .panel-status-indicators-box .system-status-icon {
+  margin: 0 !important;
+  padding: 6px !important;
+}
+
 #panel .panel-button .appindicator-trayicons-box {
   margin: 0 6px;
 }

src/gnome-shell/shell-40-0/gnome-shell.css

@@ -1974,7 +1974,7 @@ StScrollBar StButton#vhandle:active, StScrollBar StButton#hhandle:active {
 
 #panel .panel-button .system-status-icon {
   icon-size: 16px;
-  padding: 6px;
+  padding: 9px;
   margin: 0 3px;
 }
 
@@ -1986,6 +1986,11 @@ StScrollBar StButton#vhandle:active, StScrollBar StButton#hhandle:active {
   margin: 0;
 }
 
+#panel .panel-button .panel-status-indicators-box .system-status-icon {
+  margin: 0 !important;
+  padding: 6px !important;
+}
+
 #panel .panel-button .appindicator-trayicons-box {
   margin: 0 6px;
 }

src/gnome-shell/shell-42-0/gnome-shell-Compact.css

@@ -2331,6 +2331,11 @@ StScrollBar StButton#vhandle:active, StScrollBar StButton#hhandle:active {
   margin: 0;
 }
 
+#panel .panel-button .panel-status-indicators-box .system-status-icon {
+  margin: 0 !important;
+  padding: 4px !important;
+}
+
 #panel .panel-button .appindicator-trayicons-box {
   margin: 0 6px;
 }

src/gnome-shell/shell-42-0/gnome-shell-Dark-Compact.css

@@ -2335,6 +2335,11 @@ StScrollBar StButton#vhandle:active, StScrollBar StButton#hhandle:active {
   margin: 0;
 }
 
+#panel .panel-button .panel-status-indicators-box .system-status-icon {
+  margin: 0 !important;
+  padding: 4px !important;
+}
+
 #panel .panel-button .appindicator-trayicons-box {
   margin: 0 6px;
 }

src/gnome-shell/shell-42-0/gnome-shell-Dark.css

@@ -2323,7 +2323,7 @@ StScrollBar StButton#vhandle:active, StScrollBar StButton#hhandle:active {
 
 #panel .panel-button .system-status-icon {
   icon-size: 16px;
-  padding: 6px;
+  padding: 9px;
   margin: 0 3px;
 }
 
@@ -2335,6 +2335,11 @@ StScrollBar StButton#vhandle:active, StScrollBar StButton#hhandle:active {
   margin: 0;
 }
 
+#panel .panel-button .panel-status-indicators-box .system-status-icon {
+  margin: 0 !important;
+  padding: 6px !important;
+}
+
 #panel .panel-button .appindicator-trayicons-box {
   margin: 0 6px;
 }

src/gnome-shell/shell-42-0/gnome-shell.css

@@ -2319,7 +2319,7 @@ StScrollBar StButton#vhandle:active, StScrollBar StButton#hhandle:active {
 
 #panel .panel-button .system-status-icon {
   icon-size: 16px;
-  padding: 6px;
+  padding: 9px;
   margin: 0 3px;
 }
 
@@ -2331,6 +2331,11 @@ StScrollBar StButton#vhandle:active, StScrollBar StButton#hhandle:active {
   margin: 0;
 }
 
+#panel .panel-button .panel-status-indicators-box .system-status-icon {
+  margin: 0 !important;
+  padding: 6px !important;
+}
+
 #panel .panel-button .appindicator-trayicons-box {
   margin: 0 6px;
 }