Preparation for build of a unique CSS

UI/WebServerResources/scss/core/layout.scss

@@ -1,5 +1,5 @@
 // Import from sources for extends
-// ------------------------------
+// -------------------------------
 @import "../../angular-material/src/core/style/layout";
 
 // Utility classes to compensate for the the xml mandatory attribute values

UI/WebServerResources/scss/core/mixins.scss

@@ -1,3 +1,5 @@
+@import '../angular-material/src/core/style/mixins.scss';
+
 @mixin margin-selectors($before:1em, $after:1em, $start:0px, $end:0px) {
   -webkit-margin-before: $before;
   -webkit-margin-after: $after;