WordPress/wp-includes/blocks/button/editor.css

.wp-block[data-align=center]>.wp-block-button{
  margin-left:auto;
  margin-right:auto;
  text-align:center;
}

.wp-block[data-align=right]>.wp-block-button{
  text-align:right;
}

.wp-block-button{
  cursor:text;
  position:relative;
}
.wp-block-button:focus{
  box-shadow:0 0 0 1px #fff, 0 0 0 3px var(--wp-admin-theme-color);
  outline:2px solid transparent;
  outline-offset:-2px;
}
.wp-block-button[data-rich-text-placeholder]:after{
  opacity:.8;
}

.wp-block-button__inline-link{
  color:#757575;
  height:0;
  max-width:290px;
  overflow:hidden;
}
.wp-block-button__inline-link-input__suggestions{
  max-width:290px;
}
@media (min-width:782px){
  .wp-block-button__inline-link,.wp-block-button__inline-link-input__suggestions{
    max-width:260px;
  }
}
@media (min-width:960px){
  .wp-block-button__inline-link,.wp-block-button__inline-link-input__suggestions{
    max-width:290px;
  }
}
.is-selected .wp-block-button__inline-link{
  height:auto;
  overflow:visible;
}

.wp-button-label__width .components-button-group{
  display:block;
}
.wp-button-label__width .components-base-control__field{
  margin-bottom:12px;
}

div[data-type="core/button"]{
  display:table;
}

.editor-styles-wrapper .wp-block-button[style*=text-decoration] .wp-block-button__link{
  text-decoration:inherit;
}