Learn how to use common CSS layout units for layout design

Explore the use of common CSS layout units

Introduction:
In the process of web page layout, it is often necessary to use CSS to control the size and position of elements. . Choosing the right layout unit can help us better adapt to different devices and screens, and ensure the stability and responsiveness of the layout. This article will explore and introduce common CSS layout units and provide specific code examples to help readers better understand and apply them.

1. Common CSS layout units

1. Pixels (px):
   Pixels are the most common and primitive units, and they are the smallest display units on the screen. Using pixel units in layout can accurately control the size and position of elements, but it is not adaptive and responsive.

Sample code:

.container {
  width: 960px;
  margin: 0 auto;
}

.box {
  width: 200px;
  height: 200px;
}

2. Percent (%):
   Percent units are calculated relative to the size of the parent element. By using percentage units, you can achieve adaptive and responsive layout of elements, so that the web page presents a consistent effect on screens of different sizes.

Sample code:

.container {
  width: 80%;
  margin: 0 auto;
}

.box {
  width: 50%;
  height: 200px;
}

3. Viewport width (vw) and viewport height (vh):
   Viewport width and viewport height units are relative to Calculated based on the size of the browser's viewable area. These two units can be used to implement responsive layout of web pages, allowing elements to adapt adaptively to the size of the browser window.

Sample code:

.container {
  width: 80vw;
  margin: 0 auto;
}

.box {
  width: 30vw;
  height: 20vh;
}

4. Auto (auto):
   Auto units calculate size based on the element content or parent element. This unit is usually used for margin and padding, which allows elements to automatically adapt to surrounding elements or content during layout.

Sample code:

.container {
  width: 800px;
  margin: 0 auto;
}

.box {
  margin-right: auto;
  margin-left: auto;
}

2. Select the appropriate layout unit
When selecting the layout unit, you need to comprehensively consider the overall layout requirements of the page, element adaptability, and page responsive features. Here are some suggestions based on different scenarios:

1. Fixed size layout elements:
   For fixed size layout elements, such as navigation bars, sidebars, etc., you can use pixel units for precise control .
2. Adaptive and responsive layout elements:
   For elements that require adaptive and responsive layout, such as the main content area or image display area, it is recommended to use units such as percentage, vw and vh to achieve it. This maintains a consistent layout across different screen sizes.
3. Layout elements that automatically adapt to surrounding elements:
   For layout elements that need to automatically adapt to surrounding elements, such as center-aligned boxes or floating elements, you can use automatic units to achieve this. This automatically calculates size and position based on the element's content or parent element.

3. Summary
Choosing the appropriate layout unit is a key step in web page layout. It can help us achieve precise layout control, adaptive and responsive layout, and automatically adapt to surrounding elements. layout. By understanding and mastering common CSS layout units and practicing them with specific sample codes, I believe readers can better apply them to actual web development and improve the stability and responsiveness of page layout. Hope this article is helpful to readers.

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