D DevBrainBox

CSS Box Model

CSS

The CSS Box Model is a fundamental concept in web design that describes how the size of elements on a webpage is calculated. Every HTML element is considered as a box, and this box is made up of four layers:

Components Explained

1. Content

  • This is where text, images, or other elements appear.
  • You control its size using width and height.

2. Padding

  • Clears space inside the border, around the content.
  • Pushes the border outward.
  • Example: padding: 20px;

3. Border

  • A line surrounding the padding (if any) and content.
  • Can be styled using border, border-width, border-style, and border-color.
  • Example: border: 2px solid black;

4. Margin

  • Clears space outside the border, creating space between elements.
  • Example: margin: 10px;

How Element Size is Calculated (Default behavior)

  • By default, the total size of an element is:

Total Width = margin + border + padding + content width
Total Height = margin + border + padding + content height

  • To simplify sizing, use: box-sizing: border-box;

This makes the width and height include padding and border, making layouts easier to manage.

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