[Vuejs]-Of these two similar JSFiddles (using Vue.js (2.6.11) and Vuetify (2.4.0)), why does the v-card display properly in one of them, but not the other?

The second fiddle does not load stylesheets. If you add

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/vuetify@2.4.0/dist/vuetify.min.css"/>

they look pretty much the same (they use different Vuetify versions, so they look slightly different)