bailicangdu/vue2-happyfri ? reverse-engineered prompt

Build me a simple mobile friendly Vue 2 app that feels like a small quiz or practice game, with a clear start page, a question page, and a results page. It should use routing to move between screens and Vuex to keep track of the current question, selected answers, and total time spent. When the user taps an answer, save it, move to the next question, and show the final score at the end. Include a basic timer that starts when the quiz begins, and make sure there’s an easy way to reset everything and try again. Keep the design clean and easy to use on a phone, since this is mainly for learning and demo purposes. Please set it up so it runs locally with a dev server and can be built for production, and if you need to check anything, look up the current docs online.