Template Parsing Error (unknown operator: 'endblock')

**Issue: Template Parsing Error (unknown operator: 'endblock')**

**Description**
The deployed app on Render crashes with the following error:

tornado.template.ParseError: unknown operator: 'endblock' at base.html:6

This happens because the templates are written with Jinja-style tags ({% block %} ... {% endblock %}), but Tornado’s default template engine doesn’t recognize endblock.

**Steps to Reproduce**

- Open the deployed link (eventstack.onrender.com)
- Try accessing the login page
- Error appears in logs

**Proposed Fix**

Option 1: Switch Tornado to use Jinja2 as the template engine
Option 2: Update templates to use Tornado’s native syntax ({% end %} instead of {% endblock %})

**Expected Outcome**
Templates should render correctly without crashing, and the hosted site should be functional.