diff --git a/index.html b/index.html
index 685a075..be5cfbc 100644
--- a/index.html
+++ b/index.html
@@ -4,6 +4,10 @@
     <meta charset="UTF-8" />
     <!-- viewport-fit=cover so the navy header can sit under an iPhone notch and
          the action bar can clear the home indicator via env(safe-area-inset-*). -->
+    <!-- Placement rewrites this to the mount path. Without it the build is
+         rejected: relative asset refs only resolve on a deep link once the
+         base href is right. -->
+    <!--BASE_HREF-->
     <meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover" />
     <meta name="theme-color" content="#0B2A5B" />
     <meta name="apple-mobile-web-app-capable" content="yes" />