CSS (Cascading Style Sheet) is an integral part of web page production. In web page layout, CSS is usually used for positioning and layout elements. The setting of distance is a very important aspect in CSS. This article will introduce common methods and techniques for setting distance in CSS.
1. Use margin and padding
In CSS, we can use margin and padding to control the external and internal spacing of elements respectively. Their use is very simple, just add attributes to the style sheet of the corresponding element. For example:
div { margin-top: 20px; margin-right: 10px; margin-bottom: 30px; margin-left: 50px; }
The above code will set the external spacing of the top, right, bottom, and left directions of the div element, which are 20px, 10px, 30px, and 50px respectively. Similarly, we can also use the padding attribute to set internal spacing for elements.
div { padding-top: 10px; padding-right: 20px; padding-bottom: 30px; padding-left: 40px; }
The above code will set the internal spacing of the top, right, bottom, and left directions of the div element, which are 10px, 20px, 30px, and 40px respectively. It should be noted that when setting the external spacing and internal spacing, we can also use abbreviation attributes, for example:
div { margin: 20px 10px 30px 50px; padding: 10px 20px 30px 40px; }
The above code has the same effect as the previous example, but uses abbreviation attributes, which can simplify the code.
2. Use positioning attributes
Similarly, we can also use positioning attributes to set distances for elements. Among them, commonly used positioning attributes include position, top, right, bottom and left. For example, the following code will set absolute positioning for a div element and position it 100px from the left and 200px from the top.
div { position: absolute; top: 200px; left: 100px; }
In the above code, the position attribute is set to absolute, which means that the element will be positioned absolutely and will not affect the position of other elements. At the same time, the top and left attributes specify the distance of the element from the top and left, in pixels.
It should be noted that for elements that use positioning attributes, if the width and height are not set, these elements may be stacked, affecting the page layout. Therefore, usually we should also set both the width and height of the element.
3. Use flexbox layout
CSS3 introduces a new flexbox layout mode, which can more conveniently control the layout of elements on the page. In flexbox layout, we can use the justify-content and align-items properties to set horizontal and vertical spacing between elements. For example:
.container { display: flex; justify-content: space-between; align-items: center; }
In the above code, the container element .container sets the display attribute to flex, which means that the element uses flexbox layout. At the same time, the justify-content attribute is set to space-between, which means that the elements will be evenly distributed in the parent container, with a certain spacing between them. The align-items property is set to center, which means that the elements will be centered vertically aligned with a certain amount of space between them.
It should be noted that when using flexbox layout, we also need to set the flex attribute of the sub-element in order to better control the size and position of the sub-element.
The above are the common methods and techniques for setting distance in CSS introduced in this article. Whether using margin and padding, positioning attributes or flexbox layout, we can choose to use them according to specific needs. By learning these techniques, we can better control the layout of the web page and create a more beautiful interface that better meets our needs.
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