Properties: content, padding, border, margin, CSS box mode all have these properties.
CSS box model is a kind of thinking model used by CSS technology often used in web design.
Classification of boxes: different types of boxes produced by different elements may be different. What kind of box an element produces depends on its CSS display property
display:none: no generation Box
display:inline: line box
display:block: block box
Box composition:
Margin(outside Margin)-Clear the area outside the border, the outer margin is transparent.
Border-A border around the inner margin and outside the content.
Padding (inner margin)-Clear the area around the content, the inner margin is transparent.
Content-The content of the box, displaying text and images.
Example:
div {
width: 300px;
border: 25px solid green;
padding : 25px;
margin: 25 px;
} span> span>