社内向けに書いたドキュメントが好評だったので公開しちゃいます。 基本編1 本体と三角形を分けて実装します <div class="balloon"> こんにちはこんにちは! <div class="triangle"></div> </div> .balloon { position: relative; width: 200px; height: 30px; background-color: #ccc; text-align: center; } .balloon .triangle { position: absolute; bottom: -10px; left: 50%; margin-left: -10px; width: 0; height: 0; border-top: 10px solid #ccc; border-left: 10px solid transparent
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