The box model is a concept used to describe the space occupied by HTML elements on a page. Each HTML element is treated as a rectangular box, which consists of content area, padding, border and margin, which together form the box model.
Specifically, the box model consists of the following four parts:
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Content area (Content): refers to the actual content of the element, such as text, pictures, etc. The width and height settings affect the size of the content area.
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Padding: Located between the content area and the border, it is used to control the distance between the element content and the border. The size of the padding can be set through the padding attribute.
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Border: A boundary line outside the padding that surrounds the content and padding of an element. The style, color and width of the border can be set through the border attribute.
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Margin: Located outside the border, used to control the distance between the current element and other elements. You can set the size of the margins through the margin attribute.
The settings of the box model will directly affect the page layout:
● The total width and height of the element are calculated cumulatively across parts of the box model.
● The width of the element is equal to the sum of the width of the content area plus the left and right padding.
● The height of the element is equal to the sum of the height of the content area plus the top and bottom padding.
● If you set borders and margins on an element, they increase the element's size and position on the page.
● For page layout, it is very important to understand and master the box model. Proper use of each part of the box model allows you to precisely control an element's position, size, and spacing from other elements on the page.