Login form inputs lack visible focus indicator for keyboard navigation

### Overview
The login form fields do not display visible focus styling when navigated via the keyboard Tab key. Users who rely on keyboard navigation cannot tell which input is currently focused, which is a WCAG 2.1 accessibility violation (Success Criterion 2.4.7 — Focus Visible).

### Action Items
- Identify the login form component and its input elements
- Add visible `:focus` / `:focus-visible` styles (e.g. outline or box-shadow ring) to all interactive form elements
- Verify that focus order is logical and that each focusable element has a clear visual indicator
- Test with keyboard-only navigation (no mouse)

### Resources/Instructions
- [WCAG 2.4.7 Focus Visible](https://www.w3.org/WAI/WCAG21/Understanding/focus-visible.html)
- [MDN :focus-visible](https://developer.mozilla.org/en-US/docs/Web/CSS/:focus-visible)