diff --git a/README.md b/README.md
index 1c04e47..d2e67b1 100644
--- a/README.md
+++ b/README.md
@@ -200,11 +200,13 @@ Zentrale Partials:
 
 ## Asset- und Frontend-System
 
-- CSS-Layer-Entrypoint: `/web/css/app-layers.css`
+- Core-CSS-Entrypoint: `/web/css/core.css`
+- CSS-Layer/Vendor-Basis: `/web/css/app-layers.css`
 - Vendor-Overrides: `/web/css/vendor-overrides`
 - Asset-Gruppen: `/config/assets.php`
 - Template-Styles: `renderTemplateStyles('default'|'login')`
 - Seiten-Styles per Action: `Buffer::set('style_groups', ...)`
+- CSS-Contract-Check: `bin/css-contract-check.sh`
 - JS-Bootstrap:
   - `/web/js/app-boot.js` (frueh, ohne Module)
   - `/web/js/app-init.js` (Standardseiten)
diff --git a/bin/css-contract-check.sh b/bin/css-contract-check.sh
new file mode 100755
index 0000000..4867478
--- /dev/null
+++ b/bin/css-contract-check.sh
@@ -0,0 +1,95 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+script_dir="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
+repo_root="$(cd -- "${script_dir}/.." && pwd)"
+cd "${repo_root}"
+
+if ! command -v rg >/dev/null 2>&1; then
+  echo "[ERROR] rg is required for css-contract-check." >&2
+  exit 2
+fi
+
+failures=0
+
+ok() {
+  echo "[OK]  $*"
+}
+
+fail() {
+  echo "[FAIL] $*" >&2
+  failures=$((failures + 1))
+}
+
+expected_layer_order='@layer tokens, vendor, layout, vendor-overrides, components, pages, utilities;'
+if rg -Fq "${expected_layer_order}" web/css/app-layers.css; then
+  ok "Layer order declaration found in web/css/app-layers.css"
+else
+  fail "Layer order declaration is missing or changed in web/css/app-layers.css"
+fi
+
+while IFS= read -r file; do
+  expected_layer=''
+  case "${file}" in
+    web/css/base/*|modules/*/web/css/base/*)
+      expected_layer='tokens'
+      ;;
+    web/css/layout/*|modules/*/web/css/layout/*)
+      expected_layer='layout'
+      ;;
+    web/css/components/*|modules/*/web/css/components/*)
+      expected_layer='components'
+      ;;
+    web/css/pages/*|modules/*/web/css/pages/*)
+      expected_layer='pages'
+      ;;
+    web/css/vendor-overrides/*|modules/*/web/css/vendor-overrides/*)
+      expected_layer='vendor-overrides'
+      ;;
+  esac
+
+  if [[ -z "${expected_layer}" ]]; then
+    continue
+  fi
+
+  if [[ "${file}" == "web/css/pages/app-error.css" || "${file}" == "web/css/pages/app-error-debug.css" ]]; then
+    continue
+  fi
+
+  detected_layer="$(sed -n '1,120p' "${file}" | sed -nE 's/.*@layer[[:space:]]+([^[:space:]{]+).*/\1/p' | head -n1)"
+  if [[ -z "${detected_layer}" ]]; then
+    fail "${file}: missing @layer declaration near file top"
+    continue
+  fi
+
+  if [[ "${detected_layer}" != "${expected_layer}" ]]; then
+    fail "${file}: @layer ${detected_layer} does not match expected ${expected_layer}"
+  fi
+done < <(rg --files web/css modules | rg '\.css$')
+
+remote_import_pattern='@import[[:space:]]+url\(["'"'"']?(https?:)?//|@import[[:space:]]+["'"'"']?(https?:)?//'
+remote_hits="$(rg -n -g '*.css' -e "${remote_import_pattern}" web/css modules || true)"
+if [[ -n "${remote_hits}" ]]; then
+  fail "Remote CSS import detected (must vendor locally):"
+  echo "${remote_hits}" >&2
+else
+  ok "No remote CSS imports detected"
+fi
+
+if [[ ! -f web/css/core.css ]]; then
+  fail "web/css/core.css is missing"
+else
+  first_import="$(rg -n '^@import' web/css/core.css | head -n1 || true)"
+  if [[ "${first_import}" == *'app-layers.css'* ]]; then
+    ok "web/css/core.css imports app-layers.css first"
+  else
+    fail "web/css/core.css must import app-layers.css as first @import"
+  fi
+fi
+
+if [[ "${failures}" -gt 0 ]]; then
+  echo "[FAIL] CSS contract check failed with ${failures} issue(s)." >&2
+  exit 1
+fi
+
+echo "[OK] CSS contract check passed."
diff --git a/bin/qa-required.sh b/bin/qa-required.sh
index 9d264f3..fab5510 100755
--- a/bin/qa-required.sh
+++ b/bin/qa-required.sh
@@ -41,6 +41,9 @@ run_step "QG-008 Docs link integrity" \
 run_step "QG-008 Docs drift contract" \
   bin/docs-drift-check.sh
 
+run_step "CSS contract check" \
+  bin/css-contract-check.sh
+
 run_step "QG-009 Codex skills sync" \
   bin/codex-skills-sync.sh --check
 
diff --git a/config/assets.php b/config/assets.php
index c6e531b..c043afb 100644
--- a/config/assets.php
+++ b/config/assets.php
@@ -19,37 +19,9 @@ return [
                 'css/components/app-brand.css',
                 'css/components/app-file-upload.css',
             ],
-            'default' => [
-                'css/vendor-overrides/multi-select.css',
-                'css/components/app-icon-button.css',
-                'css/components/app-buttons.css',
-                'css/vendor-overrides/gridjs.css',
-                'css/layout/app-topbar.css',
-                'css/layout/app-sidebar.css',
-                'css/components/app-search.css',
-                'css/components/app-list-titlebar.css',
-                'css/components/app-details-titlebar.css',
+            'core' => [
+                'css/core.css',
                 'css/components/app-details-validation-summary.css',
-                'css/components/app-dashboard-titlebar.css',
-                'css/components/app-empty-state.css',
-                'css/components/app-details.css',
-                'css/components/app-details-card.css',
-                'css/components/app-form-info-tile.css',
-                'css/components/app-list-table.css',
-                'css/components/app-list-tabs.css',
-                'css/components/app-tabs.css',
-                'css/components/app-list-toolbar.css',
-                'css/components/app-filter-drawer.css',
-                'css/components/app-active-filter-chips.css',
-                'css/components/app-confirm-dialog.css',
-                'css/components/app-breadcrumb.css',
-                'css/components/app-tile.css',
-                'css/components/app-tooltips.css',
-                'css/components/app-lookup-field.css',
-                'css/components/app-page-editor.css',
-                'css/vendor-overrides/editorjs.css',
-                'css/components/app-page-copy.css',
-                'css/layout/app-aside-icon-bar.css',
             ],
             'login' => [
                 'css/pages/app-login.css',
@@ -65,7 +37,7 @@ return [
             ],
         ],
         'templates' => [
-            'default' => ['base', 'shared', 'default'],
+            'default' => ['base', 'core'],
             'login' => ['base', 'shared', 'login'],
             'error' => ['base', 'error'],
             'page' => ['base', 'shared', 'page-layout'],
diff --git a/docs/reference-frontend-css.md b/docs/reference-frontend-css.md
index 5c669d7..8317ec1 100644
--- a/docs/reference-frontend-css.md
+++ b/docs/reference-frontend-css.md
@@ -1,6 +1,6 @@
 # Frontend CSS
 
-Letzte Aktualisierung: 2026-03-19
+Letzte Aktualisierung: 2026-04-20
 
 ## Ziel
 
@@ -8,8 +8,10 @@ Diese Seite beschreibt die kompakte Standardstruktur für CSS in diesem Projekt:
 
 ## Struktur
 
+- `/web/css/core.css`
+  - zentraler Core-Entrypoint für die Default-Admin-Oberfläche.
 - `/web/css/app-layers.css`
-  - zentraler Entrypoint für Layer-Reihenfolge.
+  - zentrale Layer-Reihenfolge + Vendor-Basis.
 - `/web/css/base`
   - Variablen, Reset, Typografie, globale Tokens.
 - `/web/css/layout`
@@ -50,6 +52,11 @@ Kurzregel:
 Asset-Gruppen werden in `/config/assets.php` registriert.  
 Seiten laden bei Bedarf Gruppen über `Buffer::set('style_groups', ...)`.
 
+Default-Template:
+
+- `base` lädt Layer-/Token-Basis.
+- `core` lädt den konsolidierten Core-Stack über `/web/css/core.css`.
+
 Beispiel (Action):
 
 ```php
@@ -76,6 +83,7 @@ Regel: Vendor-Overrides nur für Bibliotheks-Selektoren; projektspezifische UI-S
 3. Wird die Gruppe auf der Zielseite wirklich geladen (`style_groups`)?
 4. Gibt es ungewollte Seiteneffekte auf anderen Seiten?
 5. Sind bestehende Variablen/Konventionen eingehalten?
+6. Contract-Check lokal ausführen: `bin/css-contract-check.sh`
 
 ## Module-CSS Token-Regel
 
diff --git a/web/css/core.css b/web/css/core.css
new file mode 100644
index 0000000..ce7fbb4
--- /dev/null
+++ b/web/css/core.css
@@ -0,0 +1,48 @@
+@charset "UTF-8";
+
+/*
+ * Core CSS framework entrypoint for the default admin shell.
+ * Keep imports in deterministic order; file-level @layer declarations define precedence.
+ */
+@import url("app-layers.css");
+
+/* Shared foundation used by multiple templates */
+@import url("components/app-badges.css");
+@import url("layout/app-shell.css");
+@import url("components/app-dialog.css");
+@import url("components/app-blockquote.css");
+@import url("components/app-forms.css");
+@import url("components/app-flash.css");
+@import url("components/app-brand.css");
+@import url("components/app-file-upload.css");
+
+/* Default admin experience */
+@import url("vendor-overrides/multi-select.css");
+@import url("components/app-icon-button.css");
+@import url("components/app-buttons.css");
+@import url("vendor-overrides/gridjs.css");
+@import url("layout/app-topbar.css");
+@import url("layout/app-sidebar.css");
+@import url("components/app-search.css");
+@import url("components/app-list-titlebar.css");
+@import url("components/app-details-titlebar.css");
+@import url("components/app-dashboard-titlebar.css");
+@import url("components/app-empty-state.css");
+@import url("components/app-details.css");
+@import url("components/app-details-card.css");
+@import url("components/app-form-info-tile.css");
+@import url("components/app-list-table.css");
+@import url("components/app-list-tabs.css");
+@import url("components/app-tabs.css");
+@import url("components/app-list-toolbar.css");
+@import url("components/app-filter-drawer.css");
+@import url("components/app-active-filter-chips.css");
+@import url("components/app-confirm-dialog.css");
+@import url("components/app-breadcrumb.css");
+@import url("components/app-tile.css");
+@import url("components/app-tooltips.css");
+@import url("components/app-lookup-field.css");
+@import url("components/app-page-editor.css");
+@import url("vendor-overrides/editorjs.css");
+@import url("components/app-page-copy.css");
+@import url("layout/app-aside-icon-bar.css");
diff --git a/web/css/pages/app-docs.css b/web/css/pages/app-docs.css
index a021f97..1ec1db8 100644
--- a/web/css/pages/app-docs.css
+++ b/web/css/pages/app-docs.css
@@ -1,4 +1,4 @@
-@layer components {
+@layer pages {
   /* ─── Layout ─────────────────────────────────────────────────── */
 
   .app-docs-container {