simplify

src/components/ArticleFooter.vue

 <template>
   <div class="article_footer">
-      <v-btn v-if="!webShareApiSupported || !($vuetify.breakpoint.xs || $vuetify.breakpoint.sm)" x-small depressed class="toolbar-button" rounded tabindex="0" @click="copy_link">
+      <v-btn v-if="!webShareApiSupported || !$vuetify.breakpoint.mdAndUp" x-small depressed class="toolbar-button" rounded tabindex="0" @click="copy_link">
         <v-icon small>link</v-icon> <span class = "button-text">Kopier lenke</span>
       </v-btn>