Added a custom variable for submission sections margin bottom

src/app/submission/sections/container/section-container.component.scss

 @import '../../../../styles/variables';
 
 :host /deep/ .card {
-  margin-bottom: $border-radius * 2;
+  margin-bottom: $submission-sections-margin-bottom;
 }
 
 .section-focus {

src/styles/_custom_variables.scss

@@ -25,3 +25,5 @@ $admin-sidebar-header-bg: darken($dark, 7%);
 
 $dark-scrollbar-background: $admin-sidebar-active-bg;
 $dark-scrollbar-foreground: #47495d;
+
+$submission-sections-margin-bottom: $border-radius * 2;