<div class="balloon-up">
  <p>上向きの吹き出し</p>
</div>
.balloon-up {
  position: relative;
  display: inline-block;
  margin: 1.5em 0;
  padding: 0 10px;
  min-width: 120px;
  max-width: 100%;
  color: #fff;
  font-size: 16px;
  background: #333;
}

.balloon-up:before {
  content: "";
  position: absolute;
  top: -30px;
  left: 50%;
  margin-left: -15px;
  border: 15px solid transparent;
  border-bottom: 15px solid #333;
}

External CSS

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External JavaScript

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