title: How to change placeholder's font-size but don't change the value's font-size in <input> by CSS?
body: <p>How to change placeholder's font-size but don't change the value's font-size in <code>&lt;input&gt;</code> by CSS ?</p>
  
  <p>When I focus on the <code>&lt;input&gt;</code>, placeholder's font size is already 12px, and then the value I input will be 16px. Just like this.</p>
  
  <p><strong>When I focus on the <code>&lt;input&gt;</code></strong></p>
  
  <p><a href="https://i.stack.imgur.com/Yxrsn.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Yxrsn.png" alt="enter image description here"></a></p>
  
  <p><strong>When I edit</strong></p>
  
  <p><a href="https://i.stack.imgur.com/sj3hW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/sj3hW.png" alt="enter image description here"></a></p>