Improved bookcard view for mobile

front/src/BookCard.vue

@@ -49,8 +49,8 @@ function openBook() {
 
 <style scoped>
 img {
-  max-height:200px;
-  max-width:200px;
+  max-height:100px;
+  max-width:100px;
   height:auto;
   width:auto;
 }

front/src/BooksBrowser.vue

@@ -70,8 +70,8 @@ function pageChange(newPageNumber) {
   </div>
   <div v-if="error">{{$t('bookbrowser.error', {error: error.message})}}</div>
   <div v-else-if="data">
-    <div class="books">
-      <div class="book" v-for="book in data.books" :key="book.id">
+    <div class="">
+      <div class="" v-for="book in data.books" :key="book.id">
         <BookCard v-bind="book" />
       </div>
     </div>