Greatly simplify stackable grid

src/definitions/collections/grid.less

@@ -1580,6 +1580,8 @@
   .ui.stackable.grid {
     display: block !important;
     width: auto;
+    margin-left: -(@stackableGutter / 2);
+    margin-right: -(@stackableGutter / 2);
     padding: 0em;
   }
   .ui.stackable.grid > .row > .wide.column,
@@ -1592,22 +1594,13 @@
     width: auto !important;
 
     margin: 0em 0em !important;
-    padding: (@stackableRowSpacing / 2) (@stackableGutter / 2) !important;
-
+    padding: (@stackableRowSpacing / 2) (@stackableGutter) !important;
     box-shadow: none !important;
   }
-
-  /*
-  .ui.stackable.grid + .ui.stackable.grid {
-    margin-top: (@rowSpacing / 2) !important;
-  }
-  .ui.grid + .ui.stackable.grid {
-    margin-top: (@rowSpacing / 2) !important;
-  }
-  .ui.stackable.grid + .grid {
-    margin-top: -(@rowSpacing / 2) !important;
+  .ui.stackable.grid > .row {
+    margin: 0em;
+    padding: 0em;
   }
-  */
 
   .ui.stackable.celled.grid > .column:not(.row),
   .ui.stackable.divided.grid > .column:not(.row),
@@ -1615,8 +1608,6 @@
   .ui.stackable.divided.grid > .row > .column {
     border-top: @stackableMobileBorder;
     box-shadow: none !important;
-    margin: (@stackableRowSpacing) 0em !important;
-    padding: (@stackableRowSpacing) (@stackableGutter / 2) 0em !important;
   }
   .ui.inverted.stackable.celled.grid > .column:not(.row),
   .ui.inverted.stackable.divided.grid > .column:not(.row),
@@ -1624,16 +1615,6 @@
   .ui.inverted.stackable.divided.grid > .row > .column {
     border-top: @stackableInvertedMobileBorder;
   }
-  .ui.stackable.grid > .row:first-child > .column:first-child,
-  .ui.stackable.grid > .column:first-child {
-    margin-top: 0em !important;
-    padding-top: 0em !important;
-  }
-  .ui.stackable.grid > .row:last-child > .column:last-child,
-  .ui.stackable.grid > .column:last-child {
-    margin-bottom: 0em !important;
-    padding-bottom: 0em !important;
-  }
   .ui.stackable.divided.grid > .row:first-child > .column:first-child,
   .ui.stackable.celled.grid > .row:first-child > .column:first-child,
   .ui.stackable.divided.grid > .column:not(.row):first-child,