_sass: Migrate margin-bottom: 0 to descendent styles

_sass/custom/mixins.scss

@@ -9,10 +9,6 @@
     margin-left: 0;
     margin-right: 0;
   }
-
-  >*:last-child {
-    margin-bottom: 0;
-  }
 }
 
 @mixin tight-headers() {

_sass/custom/module.scss

@@ -47,6 +47,7 @@
 .module-days {
   border-bottom: $border $border-color;
   border-top: $border $border-color;
+  margin-bottom: 0;
 
   &:first-child {
     border-top: none;

_sass/custom/schedule.scss

@@ -40,6 +40,7 @@
 
 .schedule-group {
   display: flex;
+  margin-bottom: 0;
   position: relative;
 }