Revealing the common units of CSS layout: Which ones do you need to master?

CSS Layout Unit Revealed: What do you need to know?

CSS layout units are an integral part of web design. They are used to determine the size, spacing, and positioning of elements. There are many different units to choose from in CSS, each with their own characteristics and uses. In this article, we will demystify some of the most commonly used and important CSS layout units and provide specific code examples to help you better understand and apply them.

1. Pixel (px)
   Pixel is one of the most commonly used units, which represents a pixel on the screen. When setting the size of an element in CSS, you usually use pixels as the unit. For example, you can use the following code to set the width of a div element to 200 pixels: consistent. However, using pixel units also has some disadvantages. When users browse web pages on high-resolution screens, pixel units can cause elements to appear too small.

Percent (%)

The percentage unit is relative to the size of the parent element. For example, if a div element's width is set to 50%, its width will be half the width of its parent element. The following code demonstrates how to set the width of an element using percentage units:

2. div {
     width: 200px;
   }

   
   Percent units are great for responsive layouts because they can automatically resize elements based on the screen size of different devices. However, percentage units may not work properly when the element's parent element does not have a defined width.

em

The em unit is calculated relative to the font size of the current element. If an element's font size is set to 16px, then 1em equals 16px. For example, the following code sets the font size of a paragraph element to 1.2em, which is equivalent to 1.2 times the font size of the parent element:

3. div {
     width: 50%;
   }

   
   em units are great for setting the size and spacing of elements, especially It’s when designing responsive layouts. Because it can automatically resize elements based on changes in font size. However, when the nesting level is very deep, em units can become complicated and difficult to understand.

rem

rem units are calculated relative to the font size of the root element (usually an HTML element). Unlike em units, rem units are not affected by nesting levels. For example, the following code sets the font size of a title element to 2rem, which is equivalent to 2 times the font size of the root element: Changes in the element's font size automatically resize the element. However, it may not be well supported in older browsers.

4. 
   vw and vh
vw and vh are units relative to the viewport width and viewport height. 1vw is equal to 1% of the viewport width, and 1vh is equal to 1% of the viewport height. The code below demonstrates how to use vw and vh units to set the size of an element:

p {
  font-size: 1.2em;
}

The vw and vh units are great for creating responsive layouts because it automatically adjusts to the viewport size of different devices The size of the element. However, using vw and vh units in some cases may cause elements to appear too large or too small.

5. To sum up, there are many types of CSS layout units, each with its own characteristics and uses. When choosing a layout unit, you need to make a decision based on the specific situation. If you need precise control over the size and position of elements, you can use pixel units; if you want to implement a responsive layout, you can use percentage, em, rem, or vw/vh units. By using these units flexibly, you can create beautiful, responsive web layouts.
   
I hope this article will help you understand and apply CSS layout units. Through learning and practice, you will be able to use CSS layout units more flexibly and professionally to create unique web page layouts.

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