CodePen Embed - MWMEvLd

<div class="container">
  <button>ボタン</button>  
</div>

.container {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
}

button:focus {
 outline: 6px solid red; 
}

This Pen is owned by azukiazusa1 on CodePen.

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