WordPress/wp-includes/blocks/post-excerpt/style.css

:where(.wp-block-post-excerpt){
  box-sizing:border-box;
  margin-bottom:var(--wp--style--block-gap);
  margin-top:var(--wp--style--block-gap);
}

.wp-block-post-excerpt__excerpt{
  margin-bottom:0;
  margin-top:0;
}

.wp-block-post-excerpt__more-text{
  margin-bottom:0;
  margin-top:var(--wp--style--block-gap);
}

.wp-block-post-excerpt__more-link{
  display:inline-block;
}