You are tasked with developing a web application that allows users to search for and view information about movies. The application should be built using React and should simulate a real-world app development environment. The application should have the following features:
- A search bar that allows users to search for movies by title or keyword.
- A results page that displays a list of movies matching the user's search criteria.
- A movie details page that displays detailed information about a selected movie, including its title, release date, rating, and synopsis.
- A responsive design that works well on both desktop and mobile devices.