hide back text on mobile

src/components/CreateRoom.vue

@@ -12,7 +12,7 @@
           :disabled="step > steps.NAME_SET"
         >
           <v-icon>arrow_back</v-icon>
-          <span>{{ $t("menu.back") }}</span>
+          <span class="d-none d-sm-block">{{ $t("menu.back") }}</span>
         </v-btn>
         <!-- <v-btn
           text

src/components/RoomInfo.vue

@@ -9,7 +9,7 @@
           @click.stop="$navigation.pop"
         >
           <v-icon>arrow_back</v-icon>
-          <span>{{ $t("menu.back") }}</span>
+          <span class="d-none d-sm-block">{{ $t("menu.back") }}</span>
         </v-btn>
         <div class="room-name no-upper">{{ $t("room_info.title") }}</div>
         <v-btn