Sign-in validation and error copy differ from the design

[saqibmanan]

What: There's no client-side required-field or email-format check; an empty submit goes to the server. The credential error shows under Email as "Invalid username or password." The design expects inline "Email is required." / "Password is required." and "Email or password is incorrect." under Password.
Fix: not fixed.

[saqibmanan]

Repro

• Empty submit → server round trip → "Invalid username or password." under Email. Design: "Email is required." / "Password is required." inline, no round trip.
• not-an-email + password → same server error. Design: "Enter a valid email address."
• Valid email + wrong password → "Invalid username or password." under Email. Design: "Email or password is incorrect." under Password.