diff --git a/src/components/onboarding/provisioning-status.tsx b/src/components/onboarding/provisioning-status.tsx
index ec703fd..6af854c 100644
--- a/src/components/onboarding/provisioning-status.tsx
+++ b/src/components/onboarding/provisioning-status.tsx
@@ -5,6 +5,7 @@ import Link from "next/link";
 import { useRouter } from "next/navigation";
 import { useTranslations, useFormatter } from "next-intl";
 import { Card } from "@/components/ui/card";
+import { Modal } from "@/components/ui/modal";
 import { StatusBadge } from "@/components/ui/status-badge";
 import { formatDateTime, formatRelative } from "@/lib/format";
 
@@ -250,43 +251,38 @@ export function ProvisioningStatus({ requestId, canAct }: Props) {
         </div>
 
         {confirmCancel && (
-          <div
-            role="dialog"
-            aria-modal="true"
-            className="fixed inset-0 z-50 flex items-center justify-center p-4 bg-black/60 backdrop-blur-sm"
-            onClick={(e) => {
-              if (e.target === e.currentTarget) setConfirmCancel(false);
-            }}
+          <Modal
+            open={confirmCancel}
+            onClose={() => setConfirmCancel(false)}
+            ariaLabel={t("cancelConfirmRequestTitle")}
           >
-            <div className="bg-surface-1 border border-border rounded-xl p-6 max-w-md w-full">
-              <h3 className="font-display text-lg font-semibold text-text-primary mb-2">
-                {t("cancelConfirmRequestTitle")}
-              </h3>
-              <p className="text-sm text-text-secondary mb-5">
-                {t("cancelConfirmRequestDescription")}
-              </p>
-              <div className="flex justify-end gap-2">
-                <button
-                  type="button"
-                  onClick={() => setConfirmCancel(false)}
-                  disabled={actionPending}
-                  className="text-sm px-4 py-2 rounded-lg border border-border text-text-secondary hover:text-text-primary transition-colors"
-                >
-                  {tCommon("cancel")}
-                </button>
-                <button
-                  type="button"
-                  onClick={handleCancel}
-                  disabled={actionPending}
-                  className="text-sm px-4 py-2 rounded-lg bg-red-500 text-white hover:bg-red-600 transition-colors disabled:opacity-50"
-                >
-                  {actionPending
-                    ? tCommon("loading")
-                    : t("cancelRequestConfirm")}
-                </button>
-              </div>
+            <h3 className="font-display text-lg font-semibold text-text-primary mb-2">
+              {t("cancelConfirmRequestTitle")}
+            </h3>
+            <p className="text-sm text-text-secondary mb-5">
+              {t("cancelConfirmRequestDescription")}
+            </p>
+            <div className="flex justify-end gap-2">
+              <button
+                type="button"
+                onClick={() => setConfirmCancel(false)}
+                disabled={actionPending}
+                className="text-sm px-4 py-2 rounded-lg border border-border text-text-secondary hover:text-text-primary transition-colors"
+              >
+                {tCommon("cancel")}
+              </button>
+              <button
+                type="button"
+                onClick={handleCancel}
+                disabled={actionPending}
+                className="text-sm px-4 py-2 rounded-lg bg-red-500 text-white hover:bg-red-600 transition-colors disabled:opacity-50"
+              >
+                {actionPending
+                  ? tCommon("loading")
+                  : t("cancelRequestConfirm")}
+              </button>
             </div>
-          </div>
+          </Modal>
         )}
       </Card>
     );
diff --git a/src/components/tenants/subscription-toggle.tsx b/src/components/tenants/subscription-toggle.tsx
index 0661115..e1624ab 100644
--- a/src/components/tenants/subscription-toggle.tsx
+++ b/src/components/tenants/subscription-toggle.tsx
@@ -3,6 +3,7 @@
 import { useState } from "react";
 import { useRouter } from "next/navigation";
 import { useTranslations } from "next-intl";
+import { Modal } from "@/components/ui/modal";
 
 interface Props {
   tenantName: string;
@@ -102,55 +103,50 @@ export function SubscriptionToggle({ tenantName, suspended }: Props) {
       )}
 
       {confirmOpen && (
-        <div
-          role="dialog"
-          aria-modal="true"
-          className="fixed inset-0 z-50 flex items-center justify-center p-4 bg-black/60 backdrop-blur-sm"
-          onClick={(e) => {
-            if (e.target === e.currentTarget) setConfirmOpen(false);
-          }}
+        <Modal
+          open={confirmOpen}
+          onClose={() => setConfirmOpen(false)}
+          ariaLabel={t("cancelConfirmTitle")}
         >
-          <div className="bg-surface-1 border border-border rounded-xl p-6 max-w-md w-full">
-            <h3 className="font-display text-lg font-semibold text-text-primary mb-2">
-              {t("cancelConfirmTitle")}
-            </h3>
-            <p className="text-sm text-text-secondary mb-3">
-              {t("cancelConfirmDescription")}
-            </p>
-            <ul className="text-xs text-text-muted list-disc list-inside space-y-1 mb-5">
-              <li>{t("cancelConfirmBullet1")}</li>
-              <li>{t("cancelConfirmBullet2")}</li>
-              <li>{t("cancelConfirmBullet3")}</li>
-            </ul>
+          <h3 className="font-display text-lg font-semibold text-text-primary mb-2">
+            {t("cancelConfirmTitle")}
+          </h3>
+          <p className="text-sm text-text-secondary mb-3">
+            {t("cancelConfirmDescription")}
+          </p>
+          <ul className="text-xs text-text-muted list-disc list-inside space-y-1 mb-5">
+            <li>{t("cancelConfirmBullet1")}</li>
+            <li>{t("cancelConfirmBullet2")}</li>
+            <li>{t("cancelConfirmBullet3")}</li>
+          </ul>
 
-            {error && (
-              <div className="text-xs text-red-400 bg-red-400/10 border border-red-400/20 rounded-lg px-3 py-2 mb-3">
-                {error}
-              </div>
-            )}
-
-            <div className="flex justify-end gap-2">
-              <button
-                type="button"
-                onClick={() => setConfirmOpen(false)}
-                disabled={submitting}
-                className="text-sm px-4 py-2 rounded-lg border border-border text-text-secondary hover:text-text-primary transition-colors"
-              >
-                {tCommon("cancel")}
-              </button>
-              <button
-                type="button"
-                onClick={() => toggleSuspend(true)}
-                disabled={submitting}
-                className="text-sm px-4 py-2 rounded-lg bg-amber-500 text-white hover:bg-amber-600 transition-colors disabled:opacity-50"
-              >
-                {submitting
-                  ? tCommon("loading")
-                  : t("cancelSubscriptionConfirm")}
-              </button>
+          {error && (
+            <div className="text-xs text-red-400 bg-red-400/10 border border-red-400/20 rounded-lg px-3 py-2 mb-3">
+              {error}
             </div>
+          )}
+
+          <div className="flex justify-end gap-2">
+            <button
+              type="button"
+              onClick={() => setConfirmOpen(false)}
+              disabled={submitting}
+              className="text-sm px-4 py-2 rounded-lg border border-border text-text-secondary hover:text-text-primary transition-colors"
+            >
+              {tCommon("cancel")}
+            </button>
+            <button
+              type="button"
+              onClick={() => toggleSuspend(true)}
+              disabled={submitting}
+              className="text-sm px-4 py-2 rounded-lg bg-amber-500 text-white hover:bg-amber-600 transition-colors disabled:opacity-50"
+            >
+              {submitting
+                ? tCommon("loading")
+                : t("cancelSubscriptionConfirm")}
+            </button>
           </div>
-        </div>
+        </Modal>
       )}
     </div>
   );
diff --git a/src/components/ui/modal.tsx b/src/components/ui/modal.tsx
new file mode 100644
index 0000000..b83af70
--- /dev/null
+++ b/src/components/ui/modal.tsx
@@ -0,0 +1,89 @@
+"use client";
+
+import { useEffect, useRef } from "react";
+import { createPortal } from "react-dom";
+
+interface Props {
+  open: boolean;
+  /** Called when user clicks the backdrop or presses Escape. */
+  onClose: () => void;
+  children: React.ReactNode;
+  /**
+   * ARIA label fallback when no labelled element exists inside.
+   * Optional; if you have a heading inside the modal with id, set
+   * `aria-labelledby` on a wrapper instead.
+   */
+  ariaLabel?: string;
+}
+
+/**
+ * Portal-based modal.
+ *
+ * Why a portal
+ * ------------
+ * `position: fixed` becomes positioned relative to a transformed
+ * ancestor's containing block, not the viewport, when ANY ancestor
+ * has a `transform`, `perspective`, or `filter` applied. Our
+ * `animate-in` utility sets `transform: translateY(0)` on a lot of
+ * dashboard/tenant-detail containers (because of the fade-up
+ * animation, which uses `animation-fill-mode: both` to keep the
+ * transform on after the animation finishes). That broke modals
+ * rendered as in-place children — they centred to the panel they
+ * lived in, not to the page.
+ *
+ * Rendering at `document.body` via `createPortal` escapes every
+ * containing-block ancestor and gives us true viewport coordinates.
+ *
+ * UX details
+ * ----------
+ * - Backdrop click triggers `onClose`. (Bubbling check: only fires
+ *   when the click target IS the backdrop, not the panel inside.)
+ * - Escape key triggers `onClose`. Standard modal expectation.
+ * - `body` overflow is locked while open so background content
+ *   doesn't scroll behind the modal.
+ * - Renders nothing on first paint server-side, then mounts on
+ *   client. `useEffect` gating ensures `document.body` is available;
+ *   without it Next.js SSR would throw on `document` reference.
+ */
+export function Modal({ open, onClose, children, ariaLabel }: Props) {
+  const closeRef = useRef(onClose);
+  closeRef.current = onClose;
+
+  useEffect(() => {
+    if (!open) return;
+
+    // Lock background scroll. Restore on unmount/close.
+    const previousOverflow = document.body.style.overflow;
+    document.body.style.overflow = "hidden";
+
+    const onKey = (e: KeyboardEvent) => {
+      if (e.key === "Escape") closeRef.current();
+    };
+    window.addEventListener("keydown", onKey);
+
+    return () => {
+      document.body.style.overflow = previousOverflow;
+      window.removeEventListener("keydown", onKey);
+    };
+  }, [open]);
+
+  if (!open) return null;
+  if (typeof document === "undefined") return null;
+
+  return createPortal(
+    <div
+      role="dialog"
+      aria-modal="true"
+      aria-label={ariaLabel}
+      className="fixed inset-0 z-50 flex items-center justify-center p-4 bg-black/60 backdrop-blur-sm"
+      onClick={(e) => {
+        if (e.target === e.currentTarget) onClose();
+      }}
+    >
+      <div className="bg-surface-1 border border-border rounded-xl p-6 max-w-md w-full max-h-[90vh] overflow-y-auto">
+        {children}
+      </div>
+    </div>,
+    document.body
+  );
+}