Index: chapterx-frontend/src/store/authStore.ts
===================================================================
--- chapterx-frontend/src/store/authStore.ts	(revision 99c1e45f4ac45a164229bc6f60f3b05bc26df047)
+++ chapterx-frontend/src/store/authStore.ts	(revision 3ae4bab8dcf6c40690ba2765146e7e1f70fa3a2f)
@@ -55,6 +55,6 @@
           // If the backend responded with an error (4xx/5xx), surface it to the user
           if (err?.response) {
-            const message = err.response.data?.message || err.response.data || 'Invalid email or password.'
-            throw new Error(typeof message === 'string' ? message : 'Invalid email or password.')
+            const message = err.response.data?.message || err.response.data || 'Incorrect email or password. Please try again.'
+            throw new Error(typeof message === 'string' ? message : 'Incorrect email or password. Please try again.')
           }
           // Network error / timeout — fall through to mock login
@@ -65,5 +65,5 @@
           u => u.username === emailOrUsername || u.email === emailOrUsername
         )
-        if (!user) throw new Error('User not found. Try using a quick-login option.')
+        if (!user) throw new Error('No account found with this email. Please register first.')
         set({ currentUser: user, token: null })
       },