Merge pull request #19784 from overleaf/mf-interstitial-payment-new-design-switcher

[web] Implement new interstitial payment page period switcher and header

GitOrigin-RevId: cd60909bad3c597661ba99a785ca49ed85b75af3

services/web/frontend/stylesheets/app/plans/plans-new-design.less

@@ -1011,3 +1011,13 @@
     }
   }
 }
+
+.plans-new-design.plans-interstitial-new-design {
+  padding-top: calc(var(--spacing-13) + var(--header-height));
+
+  .plans-interstitial-new-content {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+  }
+}