Changed all static inline style to CSS classes

src/components/Join.vue

@@ -38,8 +38,8 @@
         <v-row v-else class="text-center">
           <v-col>
             {{ $t("join.joining_as") }}
-            <div style="display: inline-block">
-              <v-avatar color="#e0e0e0" style="">
+            <div class="d-inline-block">
+              <v-avatar color="#e0e0e0">
                 <v-img v-if="userAvatar" :src="userAvatar" />
                 <span v-else class="white--text headline">{{
                   userAvatarLetter