fix(static): serve shared brand assets with CSS MIME

serve.py

@@ -1800,6 +1800,17 @@ def _lambda_aggregate(axes: list[float]) -> float:
 if ASSETS_DIR.exists():
     app.mount("/assets", StaticFiles(directory=str(ASSETS_DIR)), name="assets")
 
+# The shared brand injector deliberately uses absolute ``/static/...`` URLs so
+# every HTML surface (including nested ``/elite/*`` pages) resolves the same
+# zero-CDN assets. The SPA catch-all maps a request path underneath STATIC_DIR;
+# without this mount, ``/static/brand-tokens.css`` becomes
+# ``STATIC_DIR/static/brand-tokens.css`` and falls through to HTML. Browsers
+# then reject the response under strict MIME checking. Mount the already-
+# packaged public tree before the catch-all so CSS, fonts and other explicitly
+# referenced static assets retain their real media types.
+if STATIC_DIR.exists():
+    app.mount("/static", StaticFiles(directory=str(STATIC_DIR)), name="static")
+
 
 # ---------------------------------------------------------------------------
 # Health

tests/test_static_brand_assets.py

@@ -0,0 +1,33 @@
+from pathlib import Path
+
+from fastapi import FastAPI
+from fastapi.staticfiles import StaticFiles
+from fastapi.testclient import TestClient
+
+
+ROOT = Path(__file__).resolve().parents[1]
+STATIC_DIR = ROOT / "static"
+
+
+def test_brand_assets_are_packaged_and_served_as_css():
+    app = FastAPI()
+    app.mount("/static", StaticFiles(directory=str(STATIC_DIR)), name="static")
+    client = TestClient(app)
+
+    for name in ("brand-tokens.css", "brand-bridge.css"):
+        source = STATIC_DIR / name
+        assert source.is_file(), f"missing packaged brand asset: {name}"
+
+        response = client.get(f"/static/{name}")
+        assert response.status_code == 200
+        assert response.headers["content-type"].startswith("text/css")
+        assert response.content == source.read_bytes()
+
+
+def test_static_mount_precedes_the_spa_catch_all():
+    source = (ROOT / "serve.py").read_text(encoding="utf-8")
+    mount = 'app.mount("/static", StaticFiles(directory=str(STATIC_DIR)), name="static")'
+    catch_all = '@app.get("/{full_path:path}")'
+
+    assert source.count(mount) == 1
+    assert source.index(mount) < source.index(catch_all)