css does not repeat

CSS is not repeated: How to better manage and operate CSS

CSS (cascading style sheets) is one of the most important technologies in front-end development, used for page beautification, layout and interactive effects. CSS is frequently used during the development process, but many developers will encounter one or more problems: CSS style conflicts and repeated definitions, making the code difficult to manage, maintain, and debug. CSS non-duplication has become a goal pursued by many front-end developers. This article will explore the techniques and methods.

1. Use the class selector

In CSS, both the id selector and the class selector can select elements for style definition. But the id selector should only appear once in a page to uniquely identify an element. Therefore, if multiple elements need to share styles, the class selector should be used to avoid repeated definitions.

For example, we want to set the styles of multiple buttons on the page to be the same:

<button class="btn-primary">按钮1</button>
<button class="btn-primary">按钮2</button>
<button class="btn-primary">按钮3</button>

.btn-primary {
  background-color: #007bff;
  color: #fff;
  border: none;
  border-radius: 4px;
  padding: 8px 16px;
  cursor: pointer;
}

Using the class selector can easily define the style without having to repeat the definition every time.

2. Inherit styles

In CSS, child elements can inherit the style attributes of the parent element. For example, we can set the color and font of all p tags in the following way:

body {
  color: #333;
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
}

p {
  /* 继承body的color和font-family */
}

In this way, we can save the trouble of setting styles in some cases, and also make the code more concise.

3. Avoid nesting

In CSS, you can use nesting rules to apply the same style to related elements. For example:

.wrapper {
  background-color: #fafafa;
  padding: 16px;

  h1 {
    font-size: 28px;
    color: #333;
  }

  p {
    font-size: 14px;
    color: #666;
  }
}

Here, we define a wrapper class, which contains an h1 and a p element. Nested rules make it easy to define styles for related elements. However, using nested rules can easily lead to increased selector complexity and may cause style conflicts. Therefore, abuse of nested rules should be avoided.

4. Using preprocessors

Currently, the more popular CSS preprocessors include Sass, Less, Stylus, etc. They allow us to write more optimized, modular CSS code, improve code reusability, and also support advanced features such as mixins and functions.

For example, in Sass, we can define a mixin named primary to be used in multiple elements:

@mixin primary {
  background-color: #007bff;
  color: #fff;
  border: none;
  border-radius: 4px;
  padding: 8px 16px;
  cursor: pointer;
}

.btn-primary {
  @include primary;
}

In this way, we can pass the @include directive Insert the primary mixer into the .btn-primary class to avoid writing the same style repeatedly.

5. Use CSS modularization

CSS modularization is a newer way of writing CSS, which allows us to write more modular and reusable CSS code. It uses a method similar to JavaScript modules to define the component's style as an independent module, thereby avoiding global pollution and naming conflicts.

Some popular CSS modular frameworks include BEM (Block Element Modifier), SMACSS (Scalable and Modular Architecture for CSS), etc. By using these frameworks, we can define and manage CSS styles more conveniently.

Summary

CSS non-duplication is a very important goal for us to optimize front-end development. In actual development, we can use techniques such as class selectors, inherited styles, and avoiding nesting to avoid repeated CSS definitions. At the same time, using CSS preprocessors and modular frameworks in code can help us better manage and operate CSS. Improve code maintainability and reusability.

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