CSS style.css

.wp-block-tab-panel {
  max-width: 100%;
  flex-basis: 100%;
  flex-grow: 1;
  box-sizing: border-box;
}
.wp-block-tab-panel > *:first-child {
  margin-top: 0;
}
.wp-block-tab-panel > *:last-child {
  margin-bottom: 0;
}
.wp-block-tab-panel[hidden], .wp-block-tab-panel:empty {
  display: none !important;
}

.wp-block-tab-panel.wp-block.has-background,
.wp-block-tab-panel:not(.wp-block).has-background {
  padding: var(--wp--preset--spacing--30);
}