Employee Profile exact-style theme update

Applied to:
- /hrms/staff_register.php
- /hrms/staff_profile_update.php
- /hrms/staff_form.php via shared CSS/functions

Copied visual pattern from uploaded Employee Profile.html:
- Bhavdiya Group of Institutions heading
- Registered Employee Profile title
- profile photo panel
- Basic Details accordion
- Education/Experience/Research/Documents/Bank accordion blocks
- Add buttons and table headers
- form label/input alignment like col-sm-4 / col-sm-8
- dark table headings
- date placeholder DD-MM-YYYY
- Remove button near uploads

Note: External theme assets were not hotlinked except Google Public Sans font. Local CSS recreates the visual structure so pages stay fast and safe.