diff --git a/docs/INTERFACE_PATTERN_MIGRATION.md b/docs/INTERFACE_PATTERN_MIGRATION.md
index a6dc725..a62bd82 100644
--- a/docs/INTERFACE_PATTERN_MIGRATION.md
+++ b/docs/INTERFACE_PATTERN_MIGRATION.md
@@ -31,9 +31,14 @@ through declared capabilities or metadata.
 
 ## Interaction evidence
 
-- `AdminPageLayout`, `TreeSubnav`, `DataGrid`, `Dialog`, `ConfirmDialog`,
+- `WorkspaceLayout`, headerless `PageLayout`, `AdminPageLayout`, `TreeSubnav`,
+  `DataGrid`, `Dialog`, `ConfirmDialog`,
   `TableActionGroup`, `PasswordField`, `ActionBlockerHint`, and
   `DocumentationHelpLink` come from Core.
+- The administration tree and its contributed panels now share Core-owned pane
+  sizing, scrolling, content inset, responsive collapse, region labels, and
+  contextual-help identity; Access no longer carries a raw workspace or page
+  frame exception.
 - Dialog focus trapping and restoration, disabled-action tooltips, keyboard
   ordering, responsive grid overflow, and alert semantics therefore inherit
   the tested Core behavior.
diff --git a/webui/src/features/admin/AdminPage.tsx b/webui/src/features/admin/AdminPage.tsx
index bec8332..fdc3a16 100644
--- a/webui/src/features/admin/AdminPage.tsx
+++ b/webui/src/features/admin/AdminPage.tsx
@@ -12,6 +12,7 @@ import type {
 } from "@govoplan/core-webui";
 import { fetchShellAuth } from "@govoplan/core-webui";
 import { ActionBlockerHint } from "@govoplan/core-webui";
+import { PageLayout, WorkspaceLayout } from "@govoplan/core-webui";
 import { PageScrollViewport } from "@govoplan/core-webui";
 import {
   TreeSubnav,
@@ -322,15 +323,26 @@ export default function AdminPage({
   const contributionContext = { settings, auth, onAuthChange, refreshAuth, availableSections: available, selectSection };
 
   return (
-    <div className="workspace module-workspace">
-      <TreeSubnav
-        active={active}
-        nodes={adminTree}
-        onSelect={selectSection}
-        ariaLabel="i18n:govoplan-access.admin.4e7afebc"
-      />
-      <section className="workspace-content">
-        <div className="content-pad workspace-data-page">
+    <WorkspaceLayout
+      className="module-workspace"
+      primary={(
+        <TreeSubnav
+          active={active}
+          nodes={adminTree}
+          onSelect={selectSection}
+          ariaLabel="i18n:govoplan-access.admin.4e7afebc"
+        />
+      )}
+      primaryLabel="i18n:govoplan-access.admin.4e7afebc"
+      contentLabel="i18n:govoplan-access.admin.4e7afebc"
+      documentationType="admin"
+    >
+      <PageLayout
+        title="i18n:govoplan-access.admin.4e7afebc"
+        mode="workspace"
+        showHeader={false}
+        documentationType="admin"
+      >
           {contributedSection && contributedSection.render(contributionContext)}
           {!contributedSection && active === "system-mail-servers" && (
             <MailProfilesPanel settings={settings} scopeType="system" canWriteProfiles={hasScope(auth, "system:settings:write")} canManageCredentials={hasScope(auth, "system:settings:write")} canWritePolicy={hasScope(auth, "system:settings:write")} />
@@ -368,9 +380,8 @@ export default function AdminPage({
           {!contributedSection && active === "tenant-group-credentials" && <CredentialEnvelopesPanel settings={settings} scopeType="group" canWrite={hasAnyScope(auth, ["admin:settings:write", "access:credential:write"])} />}
           {!contributedSection && active === "tenant-user-file-connectors" && <FileConnectorsPanel settings={settings} scopeType="user" canWrite={hasAnyScope(auth, ["files:file:admin", "admin:settings:write"])} />}
           {!contributedSection && active === "tenant-group-file-connectors" && <FileConnectorsPanel settings={settings} scopeType="group" canWrite={hasAnyScope(auth, ["files:file:admin", "admin:settings:write"])} />}
-        </div>
-      </section>
-    </div>
+      </PageLayout>
+    </WorkspaceLayout>
   );
 }
 
diff --git a/webui/src/features/admin/GroupsPanel.tsx b/webui/src/features/admin/GroupsPanel.tsx
index 049576d..31b853a 100644
--- a/webui/src/features/admin/GroupsPanel.tsx
+++ b/webui/src/features/admin/GroupsPanel.tsx
@@ -1,4 +1,4 @@
-import { DescriptionItem, DescriptionList } from "@govoplan/core-webui";
+import { ContentGrid, DescriptionItem, DescriptionList } from "@govoplan/core-webui";
 import { useEffect, useMemo, useRef, useState } from "react";
 import { Pencil, Plus, Search, Trash2 } from "lucide-react";
 import type { FormGrid, ApiSettings, AuthInfo } from "@govoplan/core-webui";
@@ -158,10 +158,10 @@ export default function GroupsPanel({ settings, auth, canDefine, canManageMember
           <FormField label="i18n:govoplan-access.status.bae7d5be"><select value={draft.isActive ? "active" : "inactive"} disabled={!canDefine || editing !== "new" && Boolean(editing?.system_required)} onChange={(event) => setDraft({ ...draft, isActive: event.target.value === "active" })}><option value="active">i18n:govoplan-access.active.a733b809</option><option value="inactive">i18n:govoplan-access.inactive.09af574c</option></select></FormField>
           <FormField label="i18n:govoplan-access.description.55f8ebc8"><textarea rows={3} value={draft.description} disabled={!canDefine || editing !== "new" && Boolean(editing?.system_template_id)} onChange={(event) => setDraft({ ...draft, description: event.target.value })} /></FormField>
         </FormGrid>
-        <div className="admin-assignment-grid">
+        <ContentGrid columns={2} spacing="block" collapseAt="wide">
           <div><span className="form-label">i18n:govoplan-access.members.1cb449c1</span><AdminSelectionList options={users.map((user) => ({ id: user.id, label: user.display_name || user.email, description: user.email, disabled: !canManageMembers || !user.is_active || !user.account_is_active }))} selected={draft.memberIds} onChange={(memberIds) => setDraft({ ...draft, memberIds })} emptyText="i18n:govoplan-access.no_tenant_users_exist.96b4a88a" /></div>
           <div><span className="form-label">i18n:govoplan-access.inherited_roles.8def9f05</span><AdminSelectionList options={roles.map((role) => ({ id: role.id, label: role.name, description: role.description, disabled: !canAssignRoles }))} selected={draft.roleIds} onChange={(roleIds) => setDraft({ ...draft, roleIds })} emptyText="i18n:govoplan-access.no_assignable_roles_exist.a4c268c2" /></div>
-        </div>
+        </ContentGrid>
         <p className="muted small-note">i18n:govoplan-access.the_backend_evaluates_the_resulting_access_graph.f318a7dc</p>
       </Dialog>
 
diff --git a/webui/src/features/admin/SystemUsersPanel.tsx b/webui/src/features/admin/SystemUsersPanel.tsx
index 481b2a4..fae31ee 100644
--- a/webui/src/features/admin/SystemUsersPanel.tsx
+++ b/webui/src/features/admin/SystemUsersPanel.tsx
@@ -1,4 +1,4 @@
-import { DescriptionItem, DescriptionList } from "@govoplan/core-webui";
+import { ContentGrid, DescriptionItem, DescriptionList } from "@govoplan/core-webui";
 import { useEffect, useMemo, useRef, useState } from "react";
 import { Search, Pencil, Plus, Trash2 } from "lucide-react";
 import type { FormGrid, ApiSettings } from "@govoplan/core-webui";
@@ -250,10 +250,10 @@ export default function SystemUsersPanel({
           }
           <FormField label="i18n:govoplan-access.account_status.8dd86c6d"><select value={draft.isActive ? "active" : "inactive"} disabled={Boolean(editing && editing !== "new" && (!canSuspend || editing.memberships.some((membership) => membership.is_last_active_owner)))} onChange={(event) => setDraft({ ...draft, isActive: event.target.value === "active" })}><option value="active">i18n:govoplan-access.active.a733b809</option><option value="inactive">i18n:govoplan-access.inactive.09af574c</option></select></FormField>
         </FormGrid>
-        <div className="admin-assignment-grid">
+        <ContentGrid columns={2} spacing="block" collapseAt="wide">
           <div><span className="form-label">i18n:govoplan-access.system_roles.a9461aa6</span><AdminSelectionList options={roles.map((role) => ({ id: role.id, label: role.name, description: role.description, disabled: !canAssignRoles }))} selected={draft.roleIds} onChange={(roleIds) => setDraft({ ...draft, roleIds })} /></div>
           <div><span className="form-label">i18n:govoplan-access.tenant_memberships.451de736</span><AdminSelectionList options={tenants.map((tenant) => ({ id: tenant.id, label: tenant.name, description: tenant.slug, disabled: !canManageMemberships || Boolean(draft.memberships.find((item) => item.tenant_id === tenant.id)?.is_last_active_owner) }))} selected={draft.memberships.map((item) => item.tenant_id)} onChange={setMembershipSelection} /></div>
-        </div>
+        </ContentGrid>
         {editing && editing !== "new" && editing.memberships.some((membership) => membership.is_last_active_owner) && <p className="admin-protection-note">i18n:govoplan-access.this_account_is_the_last_active_operational_owne.5087839f</p>}
         <p className="muted small-note">i18n:govoplan-access.removing_a_tenant_checkbox_suspends_that_members.7c6df77d</p>
       </Dialog>
diff --git a/webui/src/features/admin/UsersPanel.tsx b/webui/src/features/admin/UsersPanel.tsx
index 366d765..cb2eb77 100644
--- a/webui/src/features/admin/UsersPanel.tsx
+++ b/webui/src/features/admin/UsersPanel.tsx
@@ -1,4 +1,4 @@
-import { DescriptionItem, DescriptionList } from "@govoplan/core-webui";
+import { ContentGrid, DescriptionItem, DescriptionList } from "@govoplan/core-webui";
 import { useEffect, useMemo, useRef, useState } from "react";
 import { KeyRound, Pencil, Plus, Search, Trash2 } from "lucide-react";
 import type { FormGrid, ApiSettings, AuthInfo } from "@govoplan/core-webui";
@@ -225,10 +225,10 @@ export default function UsersPanel({ settings, auth, canCreate, canUpdate, canSu
         </FormGrid>
         {editing === "new" && <ToggleSwitch label="i18n:govoplan-access.require_password_change_when_account_settings_ar.69bce7a3" checked={draft.passwordResetRequired} onChange={(passwordResetRequired) => setDraft({ ...draft, passwordResetRequired })} />}
         {editing && editing !== "new" && editing.is_last_active_owner && <p className="admin-protection-note">i18n:govoplan-access.this_membership_is_the_tenant_s_last_active_oper.072b247f</p>}
-        <div className="admin-assignment-grid">
+        <ContentGrid columns={2} spacing="block" collapseAt="wide">
           <div><span className="form-label">i18n:govoplan-access.groups.ae9629f4</span><AdminSelectionList options={groups.filter((group) => group.is_active).map((group) => ({ id: group.id, label: group.name, description: group.description, disabled: !canManageGroups }))} selected={draft.groupIds} onChange={(groupIds) => setDraft({ ...draft, groupIds })} emptyText="i18n:govoplan-access.no_groups_exist_yet.9cd029f6" /></div>
           <div><span className="form-label">i18n:govoplan-access.direct_roles.c4db7156</span><AdminSelectionList options={roles.map((role) => ({ id: role.id, label: role.name, description: role.description, disabled: !canAssignRoles }))} selected={draft.roleIds} onChange={(roleIds) => setDraft({ ...draft, roleIds })} emptyText="i18n:govoplan-access.no_assignable_roles_exist.a4c268c2" /></div>
-        </div>
+        </ContentGrid>
         <p className="muted small-note">i18n:govoplan-access.group_roles_and_direct_roles_are_combined_the_ba.a43c2f16</p>
       </Dialog>
 
@@ -251,7 +251,7 @@ export default function UsersPanel({ settings, auth, canCreate, canUpdate, canSu
             <DescriptionItem term={<>i18n:govoplan-access.function_facts.848b32cc</>}>{accessExplanation.function_facts.length}</DescriptionItem>
           </DescriptionList>
           <h3>i18n:govoplan-access.role_sources.6f42a672</h3>
-          {accessExplanation.role_sources.length ? <div className="admin-assignment-grid">
+          {accessExplanation.role_sources.length ? <ContentGrid columns={2} spacing="block" collapseAt="wide">
             {accessExplanation.role_sources.map((source) => <div key={sourceKey(source)}>
               <strong>{source.role_name}</strong>
               <div className="muted small-note">
@@ -263,7 +263,7 @@ export default function UsersPanel({ settings, auth, canCreate, canUpdate, canSu
               <AccessExplanationLinks organizationHref={organizationHrefForSource(source)} idmHref={idmHrefForSource(source)} />
               <div className="admin-scope-list">{source.permissions.map((scope) => <code key={scope}>{scope}</code>)}</div>
             </div>)}
-          </div> : <p className="muted small-note">i18n:govoplan-access.no_role_sources_found.91013aa5</p>}
+          </ContentGrid> : <p className="muted small-note">i18n:govoplan-access.no_role_sources_found.91013aa5</p>}
           <h3>i18n:govoplan-access.function_facts.848b32cc</h3>
           {accessExplanation.function_facts.length ? <DescriptionList>
             {accessExplanation.function_facts.map((fact) => <DescriptionItem key={fact.assignment_id} term={fact.function_name || fact.function_id}>