如何使用CSS制作评论形状

您可以在:beforeand和:afterpseudo元素上使用两个三角形.

div {
  position: relative;
  width: 100px;
  height: 40px;
  border: 4px solid black;
}
div:after, div:before {
  content: '';
  position: absolute;
  width: 0;
  height: 0;
  bottom: -9px;
  right: 20px;
  border-top: 10px solid white;
  border-right: 2px solid white;
  border-left: 10px solid transparent;
}
div:before {
  bottom: -15px;
  right: 16px;
  border-top: 15px solid black;
  border-right: 4px solid black;
  border-left: 15px solid transparent;
}