Update bootstrap-grid.scss to include box-sizing and responsive changes (#21202)

scss/bootstrap-grid.scss

@@ -3,6 +3,25 @@
 // Includes relevant variables and mixins for the regular (non-flexbox) grid
 // system, as well as the generated predefined classes (e.g., `.col-4-sm`).
 
+//
+// Box sizing, responsive, and more
+//
+
+@at-root {
+  @-ms-viewport { width: device-width; }
+}
+
+html {
+  box-sizing: border-box;
+  -ms-overflow-style: scrollbar;
+}
+
+*,
+*::before,
+*::after {
+  box-sizing: inherit;
+}
+
 
 //
 // Variables