Add responsive offcanvas classes

- Updates navbar-expand classes to de-dupe some styles—these shouldn't interfere now.
- Adds some JS to the offcanvas component to help with responsiveness

Co-Authored-By: GeoSot <geo.sotis@gmail.com>

js/src/offcanvas.js

@@ -206,6 +206,14 @@ class Offcanvas extends BaseComponent {
 
       this.hide()
     })
+
+    EventHandler.on(window, 'resize', () => {
+      // Add this check to help js be aligned with css changes on responsive offcanvas
+      if (this._isShown && getComputedStyle(this._element).position !== 'fixed') {
+        // this._backdrop.hide()
+        this.hide()
+      }
+    })
   }
 
   // Static