While working on this project, I faced several challenges that tested both my technical understanding and problem-solving skills. Setting up the backend using PHP and MySQL was one of the first hurdles—establishing a working database connection, creating the right tables with accurate data types, and managing paths for profile image storage required close attention to detail. Handling file uploads introduced its own complexity, especially when it came to validating file types and sizes, and securely saving and referencing profile pictures. On the frontend, making sure the login and signup forms looked consistent and user-friendly using CSS was at times tricky, especially when trying to ensure responsiveness. The authentication logic brought deeper challenges, like properly hashing passwords, managing sessions with $_SESSION, and redirecting users smoothly after login or signup. Debugging was often frustrating—PHP errors weren't always visible, and MySQL query issues could be hard to trace without explicitly checking for them. Time management was also a factor; even small bugs, like images not showing or sessions not holding, could take longer than expected to fix. Finally, the overall learning curve was steep, as connecting all parts of a full-stack system—frontend, backend, and database—demanded a lot of focus and adaptability.