Add this code to the Custom CSS field on the Style tab of your Pinterest Feed widget’s settings:
.global-styles,
:root {
--board-width: 20%;
--board-height: 150px;
}
.eapps-pinterest-feed-large .eapps-pinterest-feed-data-item-boards-item,
.eapps-pinterest-feed-extra-large .eapps-pinterest-feed-data-item-boards-item {
max-width: calc(var(--board-width) - 12px);
}
.eapps-pinterest-feed-data-item-boards-item-image-container {
height: var(--board-height) !important;
}