Nuxt/examples/extend-app/layouts/app.vue

<template>
  <nuxt-container>
    <img src="logo.png"/>
    <nuxt/>
  </nuxt-container>
</template>

<style scoped>
img {
  position: fixed;
  top: 20px;
  right: 20px;
  z-index: 1000;
}
</style>