.bubble {
  width: 100%;
  position: relative;
  color: #ffffff;
  font: 14px/20px "游ゴシック", "Yu Gothic", "游ゴシック体", YuGothic,
    sans-serif;
  text-align: center;
  border-radius: 25px;
  padding: 20px;
  margin-top: 30px;
  margin-bottom: 40px;
  -webkit-transition: width 0.5s, height 0.5s, -webkit-transform 0.5s; /* Safari */
  transition: width 0.5s, height 0.5s, transform 0.5s;
  background: #4197b8;
}

@media (min-width: 576px) {
  .bubble {
    width: 30%;
    font: 16px/20px "游ゴシック", "Yu Gothic", "游ゴシック体", YuGothic,
      sans-serif;
  }
  .bubble.right-side {
    margin-left: 40%;
  }

  .bubble.left-side {
    margin-left: 30%;
  }
}

.bubble:after {
  content: "";
  position: absolute;
  display: block;
  width: 0;
  z-index: 1;
  border-style: solid;
  bottom: -20px;
}

.bubble.right-side:after {
  border-width: 1px 28px 28px 0;
  border-color: transparent #4197b8 transparent transparent;
  right: 5%;
}

.bubble.left-side:after {
  border-width: 28px 28px 1px 0;
  border-color: #4197b8 transparent transparent transparent;
  left: 5%;
}