how to style v-simple-tables code example

Example 1: how to style v-simple-tables

<style scoped>
.row td {
   cursor: pointer;
}
.dataTable {
   font-size: 15px !important;
}
table.v-table thead th { .  
  font-size: 16px;
}
/* also tried table.v-table thead tr th { . */
table.v-table tbody tr td {
  font-size: 16px;
  height: 15px;
  padding: 0px;
}
</style>

Example 2: how to style v-simple-tables

<v-data-table
            :headers="headers"
            :items="patients"
            :pagination.sync="pagination"
            :total-items="totalpatients"
            :loading="loading"
            no-data-text="No patients in this registry"
            class="dataTable elevation-3"
         >
            <template v-slot:items="props">
               <tr @click="$router.push({name:'patient', params:{id: props.item.id}})" class="row" :key="props.index">
               <td class="text-xs-left">{{ props.item.lastName }}, {{ props.item.firstName }}</td>
               <td class="text-xs-center">{{ props.item.mrn }}</td>
               <td class="text-xs-center">{{props.item.dob}} Age: ({{ age(props.item.dob) }})</td>
               <td class="text-xs-center">{{ formatDate(props.item.createdAt) }}</td>
               </tr>
            </template>
         </v-data-table>