app/src/App.vue

<template>
  <div id="app">
    <Timer time="10"/>
  </div>
</template>

<script>
import Timer from './components/Timer.vue'

export default {
  name: 'App',
  components: {
    Timer
  }
}
</script>

<style>
html, body {
  height: 100%;
}
#app {
  font-family: "HelveticaNeue", "Helvetica Neue", Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-align: center;
  color: #2c3e50;
  height: 100%;
}
</style>