vue cli global body style not included in build - vue.js

Question

I added this css rule
<style>
body {
background-color: rgb(184, 182, 182);
}
#app {
...
</style>
to my App.vue file within the tag (not scoped ;-); as learned in vue mastery courses. Which BTW are a great help!
This approach also is proposed by Babacadabra in a related post.
Everything builds fine, and the locally defined (scoped) styles of a component can be found in the dist/css folder.
But my global style declaration for the background-color disappeared. As result the website layout is different than the one I tested locally (using 'vue serve'):
The background color is not applied.
What am I making wrong?
I helped myself by adding the background-color declaration directly to my index file, but that should be a patch only. I'm looking for a final solution, so the complete workflow works as expected and local and remote versions behave the same.
UPDATE (more code):
As requested here more details, i.e. the complete App.vue. I hope that is sufficient, since to my (very basic ;.-) understanding of vue the global style declarations go into this Module.
<template>
<div id="app">
<img class="vservuLogo" alt="VservuLogo" src="./assets/VservU-Logo.png">
<HelloWorld msg="Welcome to VservU GmbH Munich"/>
</div>
</template>
<script>
import HelloWorld from "./components/HelloWorld.vue";
export default {
name: "app",
components: {
HelloWorld
}
};
</script>
<style>
body {
background-color: rgb(184, 182, 182);
}
#app {
font-family: "Avenir", Helvetica, Arial, sans-serif;
-webkit-font-smoothing: antialiased;
-moz-osx-font-smoothing: grayscale;
text-align: center;
color: #2c3e50;
margin-top: 60px;
}
.vservuLogo {
width: 50%;
}
</style>
UPDATE2:
Since I could not reproduce that behavior in a new project, I guess I simply missed to clear the cache!