popup.html

<!DOCTYPE html>
<html>
<head>
  <style>
    body {
      font-family: Arial, sans-serif;
      width: 100%;
	background-color: #FF1111;
    }
    input[type="number"] {
      width: 80px;
      font-size: 16px;
      margin-right: 10px;
    }
    .input-group {
      margin-bottom: 10px;
font-size: 14px;
	color: #FFF;
    }
    #save-button {
      width: 60px;
    }
h3 {
color: #FFF;
}
  </style>
</head>
<body>
  <h3>YouTube Grid Size</h3>
  <div class="input-group">
    <label for="grid-items-input">Videos:</label>
    <input id="grid-items-input" type="number" min="1" value="6">
  </div>
  <div class="input-group">
    <label for="slim-items-input">Shorts:</label>
    <input id="slim-items-input" type="number" min="1" value="5">
  </div>
  <button id="save-button">Save</button>
  <script src="popup.js"></script>
</body>
</html>