src/components/ImageDialog.vue

@@ -2,7 +2,7 @@
   <q-dialog>
     <div class="column justify-center items-center content-center" >
       <q-btn icon="close" size="lg" class="absolute q-mt-md bg-secondary" style="top: 0px; z-index: 20000" text-color="primary" unelevated round v-close-popup />
-      <div class="absolute" style="margin: 10%; height: auto">
+      <div class="absolute" style="margin: 10%; height: auto" :style="$q.screen.lt.md ? 'margin: 0' : ''">
         <img class="full-height full-width" style="border-radius: 10px" :src="src" />
       </div>
     </div>

src/pages/ErrorNotFound.vue

 <template>
   <div class="fullscreen bg-secondary text-white text-center q-pa-md flex flex-center">
     <div>
-      <div style="font-size: 40vh" class="text-accent">
+      <div :style="$q.screen.lt.sm ? 'font-size: 30vh' : 'font-size: 40vh'" class="text-accent">
         404
       </div>
 
-      <div class="text-h3">
+      <div :class="$q.screen.lt.sm ? 'text-h4' : 'text-h3'">
         Le saviez-vous ?
       </div>
 
-      <div class="text-h4">
+      <div :class="$q.screen.lt.sm ? 'text-h5' : 'text-h4'">
         Le code 404 signifie juste "page introuvable" ! 🤯
       </div>