Manage z-indexes in variables

client/src/app/app.component.scss

@@ -16,12 +16,12 @@
   top: 0;
   width: 100%;
   background-color: var(--mainBackgroundColor);
-  z-index: 1000;
+  z-index: z(header);
   box-shadow: 0 1px 3px rgba(0, 0, 0, 0.16);
   display: flex;
 
   .top-left-block {
-    z-index: 1001;
+    z-index: z(headerLeft);
     height: $header-height;
     display: flex;
     align-items: center;

client/src/app/core/hotkeys/hotkeys.component.scss

@@ -1,3 +1,5 @@
+@import '_mixins';
+
 .cfp-hotkeys-container {
   display: flex !important;
   align-items: center;
@@ -23,7 +25,7 @@
 }
 
 .cfp-hotkeys-container.fade.in {
-  z-index: 10002;
+  z-index: z(hotkeys);
   visibility: visible;
   opacity: 1;
 }

client/src/app/menu/menu.component.scss

@@ -6,7 +6,7 @@
   height: calc(100vh - #{$header-height});
   padding: 0;
   width: $menu-width;
-  z-index: 11000;
+  z-index: z(menu);
 }
 
 menu {

client/src/sass/bootstrap.scss

@@ -19,7 +19,7 @@ $icon-font-path: '~@neos21/bootstrap3-glyphicons/assets/fonts/';
 }
 
 .dropdown {
-  z-index: 10001 !important;
+  z-index: z(dropdown) !important;
 }
 
 .dropdown-menu {
@@ -176,7 +176,11 @@ ngb-tabset.bootstrap {
 }
 
 ngb-modal-backdrop {
-  z-index: 10000 !important;
+  z-index: z(modal) - 1 !important;
+}
+
+ngb-modal-window {
+  z-index: z(modal) !important;
 }
 
 .btn-outline-tertiary {

client/src/sass/include/_variables.scss

@@ -93,8 +93,24 @@ $variables: (
   --embedBigPlayBackgroundColor: var(--embedBigPlayBackgroundColor)
 );
 
-/*** theme helper ***/
-
 @function var($variable) {
   @return map-get($variables, $variable);
 }
+
+/*** z-index groups ***/
+
+$zindex: (
+  header       :  1000,
+    /* header context */
+    headerLeft :    10,
+  menu         : 11000,
+  dropdown     : 12000,
+  loadbar      : 13000,
+  modal        : 14000,
+  notification : 15000,
+  hotkeys      : 16000
+);
+
+@function z($label) {
+  @return map-get($zindex, $label);
+}

client/src/sass/loading-bar.scss

@@ -1,3 +1,4 @@
+@import '_mixins';
 // Thanks: https://github.com/aitboudad/ngx-loading-bar/blob/master/loading-bar.css
 
 /* Make clicks pass-through */
@@ -20,7 +21,7 @@
 
   background: var(--mainColor);
   position: fixed;
-  z-index: 10002;
+  z-index: z(loadbar);
   top: 0;
   left: 0;
   width: 100%;
@@ -50,7 +51,7 @@
 #loading-bar-spinner {
   display: block;
   position: fixed;
-  z-index: 10002;
+  z-index: z(loadbar);
   top: 10px;
   left: 10px;
 }

client/src/sass/primeng-custom.scss

@@ -383,8 +383,7 @@ p-inputswitch {
 
 p-toast {
   .ui-toast {
-    // Modal is 10005
-    z-index: 10010 !important;
+    z-index: z(notification) !important;
   }
 
   .ui-toast-message {