[Vuejs]-Vuetify v-data-table doesn't increase font size

You can see that specificity is required to get what you want here. Using the code pen from the Vuetify documentation, these changes work on the v-data-table. Keep in mind that Vuetify has some weird CSS workarounds required without using loaders, like needing to use instead of or using !important tags.

https://vuetifyjs.com/en/components/data-tables
(select “Edit in CodePen” to test these)”

.v-data-table th {
  font-size: 20px;
}

.v-data-table td {
  font-size: 20px;
}

Details on loaders and CSS details:
Vuetify – CSS not working (taking effect) inside component