We set the box sizing property of all items to the bounding box using the universal selector *. This ensures that the total width and height of each element include its content, padding, and border. This makes it easy to modify the content and make it fit its specifications.

/* Default box-sizing */
.deepak {
  width: 300px;
  padding: 20px;
  border: 5px solid black;
  margin: 10px;
}
/* Apply border-box to all elements */
* {
  box-sizing: border-box;
}

Hello Ganesan,
Please check the below URL:
https://www.freecodecamp.org/news/how-to-use-the-css-box-sizing-property/