What are the common layout units in CSS?

Common css layout units include pixels, percentages, em, rem, inches, centimeters, millimeters, pixel density, viewport and percentage. Detailed introduction: 1. Pixel, usually used to precisely control the size and position of elements; 2. Percentage, usually used to implement responsive layout; 3. em, usually used to control font size and line height; 4. rem, usually used Used to achieve responsive layout; 5. Inches, usually used for print styles; 6. Centimeters, usually used for print styles; 7. Millimeters, usually used to precisely control the size and position of elements; 8. Pixel density, etc.

Operating system for this tutorial: Windows 10 system, CSS3 version, DELL G3 computer.

CSS is a language used to describe the style and layout of web pages. In CSS, there are many different units used for measuring and laying out web page elements. Here are some common CSS layout units:

Pixel (px): Pixel is the most commonly used unit in CSS and represents a point on the screen. Pixel size depends on the screen resolution and is often used to precisely control the size and position of elements. For example, set the width of an element to 100px means that the element takes up 100 pixels of width on the screen.

Percent (%): Percent represents the size or position of an element relative to the size or position of the parent element. For example, setting the width of an element to 50% means that the element takes up 50% of the parent element. width. Percentages are often used to implement responsive layouts because they automatically adjust based on the size of the parent element.

em: em is a relative unit that represents a multiple of an element's size or position relative to the current font size. For example, if the current font size is 16px, then 1em equals 16px. If the font size is 20px, then 1em is equal to 20px. ems are commonly used to control font size and line height.

rem: rem is a relative unit that represents a multiple of the size or position of an element relative to the size or position of the root element. For example, if the size of the root element is 16px, then 1rem is equal to 16px. If the size of the root element is 20px, then 1rem equals 20px. rems are often used to implement responsive layouts because they automatically adjust based on the size of the root element.

Inch (in): Inch is an absolute unit in CSS, which represents a length on the screen. 1 inch equals 2.54 centimeter. Inches are often used in print styles because they ensure consistent dimensions across different printers and papers.

Centimeter (cm): Centimeter is an absolute unit in CSS, which represents a length on the screen. 1 centimeter equals 0.39 inch. Centimeters are often used for print styles because they ensure consistent dimensions across different printers and papers.

Millimeter (mm): Millimeter is an absolute unit in CSS, which represents a length on the screen. 1 millimeter equals 0.039 inches. Millimeters are often used to precisely control the size and position of elements.

Pixel density (dppx): Pixel density is a relative unit in CSS that represents a multiple of the size or position of an element relative to device pixels. For example, if the device has a pixel density of 1, then 1dppx Equal to 1px. If the device has a pixel density of 2, then 1dppx is equal to 2px. Pixel density is often used to implement responsive layouts as they automatically adjust based on device pixel density.

Viewport (viewport): Viewport is a relative unit in CSS, which represents a multiple of the size or position of an element relative to the size of the viewport. For example, if the viewport size is 600px, then 1viewport is equal to 600px. If the viewport size is 800px, then 1viewport is equal to 800px. Viewports are often used to implement responsive layouts because they automatically adjust to the device screen size.

Percent (%): Percent is a relative unit in CSS, which represents the size or position of an element as a percentage of the size or position of the parent element. For example, if the parent element's size is 100px, then 50% Indicates that the size of the element is 50px. If the size of the parent element is 200px, then 50% means that the size of the element is 100px. Percentages are often used to implement responsive layouts because they automatically adjust based on the size of the parent element.

The above are some common CSS layout units. Different units are suitable for different scenarios, and you need to choose the appropriate unit according to specific needs.

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