RohitGautam30/Cold-Mailer ? reverse-engineered prompt

Build me a simple web app for sending personalized cold emails for internship and job outreach.

It should let me upload a resume as a PDF, replace it anytime, then enter one recipient or a small list of recipients, along with a custom subject and message. When I send, the app should automatically attach the latest uploaded resume and send the email through SMTP using my login details from environment variables. I want a clean, responsive interface with clear status messages so I can see if each email sent successfully or failed.

Please keep it straightforward and practical, with Flask on the backend and basic HTML, CSS, and JavaScript for the frontend. Make sure the uploaded resume is stored safely and reused for future sends. If you need to look up current docs online, go ahead. I also want the app to feel usable right away, so include the main page, upload flow, email form, and sending feedback in one polished experience.