diff --git a/CLAUDE.md b/CLAUDE.md
index 3d2642c4f..c65d2a24a 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -154,6 +154,8 @@ the primitive, not N components.
 | Full-bleed page hero (centered) | `<PageHero theme title subtitle>` | `components/layout/PageHero.tsx` | a one-off `<section>` with a bespoke `<h1>` type string |
 | Page-section vertical rhythm / tinted band | `<Section density tone>` | `components/layout/Section.tsx` | hardcoded `py-16 sm:py-20 …` |
 | Mobile bottom tab bar (`<lg`) | `<BottomNav items ariaLabel more>` | `components/layout/BottomNav.tsx` | a `fixed bottom-0 … flex` `<nav>` + tab loop |
+| Edge overlay (right sheet / bottom sheet) | `<Drawer isOpen onClose side ariaLabel>` | `components/ui/Drawer.tsx` | a hand-rolled `fixed inset-0` portal + backdrop + focus-trap |
+| Centered dialog | `<Modal isOpen onClose title>` | `components/ui/Modal.tsx` | a bespoke centered overlay |
 | Active/inactive nav item classes | `navLinkClass(shape, active)` / `NAV_STATE` | `lib/design/nav.ts` | inline `text-action` / `ring-action/20` ladders |
 
 Rules:
@@ -171,11 +173,12 @@ Rules:
   `<Card>`/`<Panel>` both resolve to it. `rounded-lg`, missing border, or
   `shadow-xs` on a static card is drift — fix it, don't copy it.
 
-Deliberately NOT unified (yet): the right-edge **drawer/sheet** overlay
-(MessageSidebar, MobileMenu, DashboardMobileNav sheet) — a shared `<Drawer>`
-with focus-trap + scroll-lock is the next chrome primitive; until it lands,
-match MobileMenu's implementation (scrim `bg-black/40 backdrop-blur-xs`, focus
-trap via `useFocusTrap`, body scroll-lock) and never `bg-opacity-*`.
+Every edge overlay goes through `<Drawer>` (right sheet or `side="bottom"`) —
+it owns the portal, `useFocusTrap` (Escape / initial focus / Tab cycle / focus
+restore), body scroll-lock, and the `bg-black/40 backdrop-blur-xs` scrim. Pass
+panel size via `className`, viewport gating via `rootClassName` (`xl:hidden` /
+`lg:hidden`). Never hand-roll a `fixed inset-0` overlay and never `bg-opacity-*`
+(use `bg-black/NN`). Centered dialogs use `<Modal>`, its sibling.
 
 ### Mobile-first = ACTION-first, not stats-first
 
diff --git a/src/components/dashboard/DashboardMobileNav.tsx b/src/components/dashboard/DashboardMobileNav.tsx
index 1f9a54e3c..477da6bde 100644
--- a/src/components/dashboard/DashboardMobileNav.tsx
+++ b/src/components/dashboard/DashboardMobileNav.tsx
@@ -1,13 +1,12 @@
 'use client'
 
 import { useEffect, useMemo, useState } from 'react'
-import { createPortal } from 'react-dom'
 import { X } from 'lucide-react'
 import { Link, usePathname } from '@/i18n/navigation'
 import { Button } from '@/components/ui/button'
 import { BottomNav } from '@/components/layout/BottomNav'
+import { Drawer } from '@/components/ui/Drawer'
 import { navLinkClass } from '@/lib/design/nav'
-import { useFocusTrap } from '@/hooks/useFocusTrap'
 import {
   DASHBOARD_CATEGORIES,
   getAllDashboardCards,
@@ -53,20 +52,6 @@ export function DashboardMobileNav({
     [role, isStaff, isSuperAdmin, isTechnician],
   )
   const [moreOpen, setMoreOpen] = useState(false)
-  const [mounted, setMounted] = useState(false)
-  const sheetRef = useFocusTrap<HTMLDivElement>(moreOpen, () => setMoreOpen(false))
-
-  useEffect(() => setMounted(true), [])
-
-  // Lock body scroll while the sheet is open.
-  useEffect(() => {
-    if (!moreOpen) return
-    const prev = document.body.style.overflow
-    document.body.style.overflow = 'hidden'
-    return () => {
-      document.body.style.overflow = prev
-    }
-  }, [moreOpen])
 
   // Close the sheet on navigation.
   useEffect(() => {
@@ -101,19 +86,15 @@ export function DashboardMobileNav({
         more={{ label: 'Mehr', ariaLabel: 'Mehr anzeigen', onClick: () => setMoreOpen(true), expanded: moreOpen }}
       />
 
-      {/* "Mehr" bottom sheet */}
-      {mounted && moreOpen && createPortal(
-        <div className="fixed inset-0 z-50 lg:hidden" role="dialog" aria-modal="true" aria-label="Dashboard-Menü">
-          <Button
-            variant="ghost"
-            aria-label="Schliessen"
-            onClick={() => setMoreOpen(false)}
-            className="absolute inset-0 h-full w-full rounded-none bg-black/40 p-0 backdrop-blur-xs hover:bg-black/40"
-          />
-          <div
-            ref={sheetRef}
-            className="absolute inset-x-0 bottom-0 max-h-[80vh] overflow-y-auto rounded-t-2xl border-t border-subtle bg-surface-base p-4 pb-[max(1rem,env(safe-area-inset-bottom))] shadow-card"
-          >
+      {/* "Mehr" bottom sheet — Drawer supplies the portal, focus-trap and scroll-lock. */}
+      <Drawer
+        isOpen={moreOpen}
+        onClose={() => setMoreOpen(false)}
+        side="bottom"
+        ariaLabel="Dashboard-Menü"
+        rootClassName="lg:hidden"
+        className="overflow-y-auto p-4 pb-[max(1rem,env(safe-area-inset-bottom))] shadow-card"
+      >
             <div className="mb-3 flex items-center justify-between">
               <span className="text-sm font-semibold text-text-primary">Alle Bereiche</span>
               <Button
@@ -152,10 +133,7 @@ export function DashboardMobileNav({
                 </div>
               ))}
             </div>
-          </div>
-        </div>,
-        document.body,
-      )}
+      </Drawer>
     </>
   )
 }
diff --git a/src/components/layout/MobileMenu.tsx b/src/components/layout/MobileMenu.tsx
index adfc0443d..6ab256095 100644
--- a/src/components/layout/MobileMenu.tsx
+++ b/src/components/layout/MobileMenu.tsx
@@ -1,12 +1,11 @@
 'use client'
 
-import { useEffect, useState } from 'react'
+import { useState } from 'react'
 import { Link } from '@/i18n/navigation'
-import { useFocusTrap } from '@/hooks/useFocusTrap'
 import { useRouter } from 'next/navigation'
 import { X, ChevronDown, ExternalLink, ArrowRight } from 'lucide-react'
-import { createPortal } from 'react-dom'
 import { useTranslations } from 'next-intl'
+import { Drawer } from '@/components/ui/Drawer'
 import { NavigationItem } from '@/config/navigation'
 import { ORG } from '@/config/org'
 import { Button } from '@/components/ui/button'
@@ -47,27 +46,9 @@ export function MobileMenu({
     if (!key) return null
     try { return tBadge(key as never) } catch { return key }
   }
-  // Escape-to-close, initial focus, focus restore (to the hamburger trigger)
-  // and the Tab trap all live in the shared hook; attach its ref to the panel.
-  const menuPanelRef = useFocusTrap<HTMLDivElement>(isOpen, onClose)
+  // Portal, backdrop, focus-trap (Escape / initial focus / Tab cycle / focus
+  // restore) and body scroll-lock all live in <Drawer>.
   const [openDropdown, setOpenDropdown] = useState<string | null>(null)
-  const [mounted, setMounted] = useState(false)
-
-  useEffect(() => {
-    // Defer setState to avoid synchronous update during effect
-    const frame = requestAnimationFrame(() => setMounted(true))
-    return () => cancelAnimationFrame(frame)
-  }, [])
-
-  // Lock body scroll while the menu is open.
-  useEffect(() => {
-    if (!isOpen) return
-    const prevOverflow = document.body.style.overflow
-    document.body.style.overflow = 'hidden'
-    return () => {
-      document.body.style.overflow = prevOverflow
-    }
-  }, [isOpen])
 
   const handleNavigation = (href: string) => {
     if (href === '#') return
@@ -82,44 +63,18 @@ export function MobileMenu({
     setOpenDropdown(openDropdown === itemName ? null : itemName)
   }
 
-  if (!mounted || !isOpen) return null
-
   // Separate primary nav from action items
   const primaryItems = navigationItems.filter(item => !item.highlight)
   const actionItems = navigationItems.filter(item => item.highlight)
 
-  return createPortal(
-    <div
-      className="fixed inset-0 z-100 xl:hidden"
-      role="dialog"
-      aria-modal="true"
-      aria-label="Mobile Navigation"
+  return (
+    <Drawer
+      isOpen={isOpen}
+      onClose={onClose}
+      side="right"
+      ariaLabel="Mobile Navigation"
+      rootClassName="xl:hidden"
     >
-      {/* Backdrop */}
-      <div
-        className={cn(
-          "fixed inset-0 bg-black/40 backdrop-blur-xs",
-          "transition-opacity duration-300",
-          isOpen ? "opacity-100" : "opacity-0"
-        )}
-        onClick={onClose}
-        aria-hidden="true"
-      />
-
-      {/* Menu Panel */}
-      <div
-        ref={menuPanelRef}
-        tabIndex={-1}
-        className={cn(
-          "fixed inset-y-0 right-0 z-101 w-full sm:max-w-md",
-          // Border-only separation matches the rest of the design system —
-          // the translucent backdrop already provides the plane lift.
-          "bg-surface-base border-l border",
-          "flex flex-col",
-          "transition-transform duration-300 ease-out",
-          isOpen ? "translate-x-0" : "translate-x-full"
-        )}
-      >
         {/* Header */}
         <div className="flex items-center justify-between px-6 py-4 border-b border-subtle dark:border-white/6">
           <Button type="button" variant="ghost" onClick={onClose} className="cursor-pointer bg-transparent border-none p-0 h-auto">
@@ -392,9 +347,7 @@ export function MobileMenu({
             </div>
           )}
         </div>
-      </div>
-    </div>,
-    document.body
+    </Drawer>
   )
 }
 
diff --git a/src/components/messaging/MessageSidebar.tsx b/src/components/messaging/MessageSidebar.tsx
index 9c754321f..841146208 100644
--- a/src/components/messaging/MessageSidebar.tsx
+++ b/src/components/messaging/MessageSidebar.tsx
@@ -19,6 +19,7 @@ import { formatDateShort, formatTime } from '@/lib/date-formats'
 import Heading from '@/components/ui/Heading'
 import { Button } from '@/components/ui/button'
 import { Input } from '@/components/ui/input'
+import { Drawer } from '@/components/ui/Drawer'
 
 interface Conversation {
   id: string
@@ -130,11 +131,8 @@ export function MessageSidebar({ isOpen, onClose, initialConversationId }: Messa
     conv.title?.toLowerCase().includes(searchQuery.toLowerCase())
   )
 
-  if (!isOpen) return null
-
   return (
-    <div className="fixed inset-0 bg-black bg-opacity-50 z-50 flex">
-      <div className="ml-auto w-full max-w-md bg-surface-base h-full flex flex-col">
+    <Drawer isOpen={isOpen} onClose={onClose} side="right" ariaLabel={t('title')}>
         {/* Header */}
         <div className="p-4 border-b border-strong flex items-center justify-between">
           <Heading level={2} className="text-lg font-semibold">{t('title')}</Heading>
@@ -295,8 +293,7 @@ export function MessageSidebar({ isOpen, onClose, initialConversationId }: Messa
             </div>
           )}
         </div>
-      </div>
-    </div>
+    </Drawer>
   )
 }
 
diff --git a/src/components/ui/Drawer.tsx b/src/components/ui/Drawer.tsx
new file mode 100644
index 000000000..ddeced331
--- /dev/null
+++ b/src/components/ui/Drawer.tsx
@@ -0,0 +1,107 @@
+'use client'
+
+/**
+ * Drawer — the edge-anchored overlay primitive (the sibling of <Modal>, which
+ * is the centered dialog). The SSOT for right-side sheets (mobile menu, message
+ * sidebar) and bottom sheets (dashboard "Mehr").
+ *
+ * Before this primitive, three overlays hand-rolled the same shell and drifted:
+ * MobileMenu (portal + focus-trap + scroll-lock, the good reference),
+ * DashboardMobileNav's sheet (same, duplicated), and MessageSidebar (NO portal,
+ * NO focus-trap, NO scroll-lock, backdrop that didn't close, deprecated
+ * `bg-opacity-50`). Drawer gives all three: a portal (so it escapes transformed
+ * ancestors like the smart-hiding header), the shared `useFocusTrap`
+ * (initial focus + Tab cycle + Escape + focus restore), body scroll-lock, and a
+ * click-to-close backdrop.
+ *
+ * Caller owns the panel *contents* (header, body) and the open state. The panel
+ * width/height is a sensible default per side; override via `className`. Use
+ * `rootClassName` for viewport gating (e.g. `xl:hidden`, `lg:hidden`).
+ */
+
+import { useEffect, useState, type ReactNode } from 'react'
+import { createPortal } from 'react-dom'
+import { useFocusTrap } from '@/hooks/useFocusTrap'
+import { cn } from '@/lib/utils'
+
+type DrawerSide = 'right' | 'bottom'
+
+interface DrawerProps {
+  isOpen: boolean
+  onClose: () => void
+  /** Which edge the panel is anchored to. Default 'right'. */
+  side?: DrawerSide
+  /** Accessible name for the dialog (required — it's `aria-label`). */
+  ariaLabel: string
+  /** Classes for the sliding panel (width / max-height / padding overrides). */
+  className?: string
+  /** Classes for the root portal layer — e.g. `xl:hidden` / `lg:hidden`. */
+  rootClassName?: string
+  children: ReactNode
+}
+
+// Panel shape per side. `bg-surface-base` + border matches the design system
+// (border-only separation; the translucent backdrop supplies the plane lift).
+const SIDE_PANEL: Record<DrawerSide, string> = {
+  right: 'inset-y-0 right-0 w-full sm:max-w-md border-l border',
+  bottom: 'inset-x-0 bottom-0 max-h-[85vh] rounded-t-2xl border-t border-subtle',
+}
+
+export function Drawer({
+  isOpen,
+  onClose,
+  side = 'right',
+  ariaLabel,
+  className,
+  rootClassName,
+  children,
+}: DrawerProps) {
+  // Escape-to-close, initial focus, Tab trap and focus restore all live in the
+  // shared hook; attach its ref to the panel.
+  const panelRef = useFocusTrap<HTMLDivElement>(isOpen, onClose)
+  // Portals need the document — mount after first client render.
+  const [mounted, setMounted] = useState(false)
+  useEffect(() => {
+    const frame = requestAnimationFrame(() => setMounted(true))
+    return () => cancelAnimationFrame(frame)
+  }, [])
+
+  // Lock body scroll while open.
+  useEffect(() => {
+    if (!isOpen) return
+    const prev = document.body.style.overflow
+    document.body.style.overflow = 'hidden'
+    return () => {
+      document.body.style.overflow = prev
+    }
+  }, [isOpen])
+
+  if (!mounted || !isOpen) return null
+
+  return createPortal(
+    <div
+      className={cn('fixed inset-0 z-100', rootClassName)}
+      role="dialog"
+      aria-modal="true"
+      aria-label={ariaLabel}
+    >
+      <div
+        className="fixed inset-0 bg-black/40 backdrop-blur-xs"
+        onClick={onClose}
+        aria-hidden="true"
+      />
+      <div
+        ref={panelRef}
+        tabIndex={-1}
+        className={cn(
+          'fixed z-101 flex flex-col bg-surface-base focus:outline-hidden',
+          SIDE_PANEL[side],
+          className,
+        )}
+      >
+        {children}
+      </div>
+    </div>,
+    document.body,
+  )
+}