fix: media print css (#2593)

client/themes/default/scss/app.scss

@@ -966,13 +966,13 @@ @media print {
     }
   }
 
-  .v-content {
+  .v-main {
     padding: 0 !important;
     font-size: 14px;
     background-color: #FFF;
   }
 
-  .v-content .contents {
+  .v-main .contents {
     color: #000;
     background-color: #FFF;