Using CSS variables can effectively improve style maintainability. 1. By unifying the design of basic elements of the system, such as colors, fonts, etc., global calls and modifications are realized, such as defining --color-primary and reusing them in multiple components; 2. Component-level variables support local customization, such as setting independent margins and background colors for card components; 3. Dynamically switch variable values in combination with media query to achieve responsive design; 4. Good naming and organizational methods, such as semantic naming and module grouping, help team collaboration. Use CSS variables reasonably to make the project easier to maintain and expand.

It is a very practical way to use CSS to customize properties (variables) to improve maintainability. Especially when the project is getting bigger and the style is becoming more and more complex, the rational use of variables can reduce duplicate code, unify the style, and make it easier to adjust later.

The following is based on several common scenarios and talk about how to use CSS variables well to truly improve the maintainability of the project.

1. Unify the basic elements of the design system such as color and font

Many front-end projects have a set of design specifications, such as main tone, auxiliary colors, font size, spacing, etc. Writing these commonly used values as variables can be called uniformly throughout the project.

 :root {
  --color-primary: #007bff;
  --font-size-base: 16px;
  --spacing-unit: 1rem;
}

Then use in the style:

 .button {
  background-color: var(--color-primary);
  font-size: var(--font-size-base);
  padding: var(--spacing-unit);
}

The advantage of doing this is: changing a place will affect the overall situation . For example, to change the brand color, you only need to change --color-primary variable, and you don’t need to find color value replacement in each class.

2. Local customization of component-level variables

Although global variables are very useful, sometimes we want a component to have its own set of configurations, such as a special card component that requires different margins or background colors.

You can do this:

 .card {
  --card-padding: 1.5rem;
  --card-bg: #f8f9fa;

  padding: var(--card-padding);
  background-color: var(--card-bg);
}

This method makes the style logic inside the component clearer and facilitates reuse and modification. If you want to change the style of this card in the future, just change the variables in the component directly, without changing the specific style rules.

3. Implement responsive variable control in combination with media queries

In responsive design, we often change the font size, spacing, etc. according to different screen sizes. CSS variables can be used to dynamically switch values with media query.

 :root {
  --font-size-heading: 24px;
}

@media (min-width: 768px) {
  :root {
    --font-size-heading: 32px;
  }
}

Then use in the title style:

 h1 {
  font-size: var(--font-size-heading);
}

This allows variable values to be automatically switched on different devices without having to rewrite a bunch of styles for each breakpoint. The logic is clearer and the structure is cleaner.

4. Pay attention to variable naming and organization

Variables are not just named casually. Good naming habits will make teamwork smoother. suggestion:

• Use semantic naming, such as --color-primary instead of --blue
• Grouped by module or function, such as --btn-padding , --modal-bg
• Manage global variables in a centralized file or code block

For example:

 /* Theme color*/
--color-primary: #007bff;
--color-success: #28a745;

/* Font related*/
--font-size-base: 16px;
--font-weight-bold: 700;

/* Layout spacing*/
--spacing-sm: 0.5rem;
--spacing-md: 1rem;
--spacing-lg: 2rem;

This organization seems simple, but it is very practical in multi-person collaboration. Others can tell how to use it and where to modify it at a glance.

Use CSS variables not to show off skills, but to make the style more manageable and flexible. At the beginning, you may feel that writing a few more variables is troublesome, but once the project scale is increased, you will find that these small changes actually save a lot of effort to go back.

Basically that's it.

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