What is the Best Way to Optimize CSS?

What is the Best Way to Optimize CSS?

As web developers, we are all aware of the importance of CSS in making our websites look aesthetically pleasing. However, with the increasing complexity of modern web designs, CSS files have become bulkier and more intricate than ever. This can lead to slow page loading speeds, poor user experiences, and decreased search engine rankings. Therefore, it’s vital for developers to find the best way to optimize CSS files and make them as efficient as possible. 

In this blog post, we will explore the best ways to optimize CSS and improve the performance of your website. From reducing file size and using selectors more efficiently to leveraging browser caching, we’ll cover all the tips and tricks you need to know to optimize your CSS files. So, let’s dive in and learn how to make our websites lightning-fast!

Why Optimizing CSS is Important

When it comes to optimizing for great user experience, a large chunk of developers usually optimize huge image files which greatly impacts website load speed, and then optimizing Javascript files seems the next logical solution. But unoptimized CSS files too can have the same negative aspect on website performance as unoptimized Images and Javascript have on your website.

Here are a few reasons why Optimizing CSS files is important:-

Rendering getting blocked by CSS

CSS is an important part of the critical rendering path of the site, i.e., the minimum amount of information of the website required to render its first pixel. In simple terms, when CSS is being parsed by the browser, it will block all other resources from loading including HTML.

CSS Files grows

As the developer tries to beautify each component of the website, the use and complexity of the CSS grows exponentially, as the project gets bigger so does CSS too, which easily becomes tough to maintain and parse it.

External Linked CSS can affect parsing

External stylesheets such as fonts, stop HTML parsing to fetch fonts or other CSS files, and once it has been processed, then only move forward with the remaining HTML parsing.

CSS hinders interactivity

CSS is render-blocking, the browser always prioritizes CSS when it is loading a page, it basically blocks HTM and processes CSS files first. This directly increases the time of interactivity of the website, meaning the user cant interact with the website until all the CSS files have been processed.

DOM Construction Diagram

Also Read, 10 Crazy Useful Google Chrome Extensions for a Developer you Need to Have!



The best way to Optimize CSS

Here are a few methods you can use in order to optimize your CSS file,

Reducing CSS File Size

A simple and efficient way to optimize your CSS files is by reducing them. There are basically three main methods by which you can reduce your CSS files are,

CSS Minification

Minification is a process by which you remove all the whitespaces and extraneous characters in CSS. For example, It would turn this (59 characters):

.conatiner {
   color: white;
   background-color: black;

Into this (49 characters):


Here are some tools to minify your CSS:

  • For manual minification, you can use CSSNano or csso.
  • Larger sites that can benefit from automated workflows can use Gulp or Webpack.

Reducing CSS File’s Length

You can also remove unnecessary codes from css likes,

  • Duplicate code
  • Use shorthand properties to reduce the amount of code needed.
  • Optimizing your CSS code using Inheritance properties, for example, if we apply the color property to a parent, the same color’s properties are also applied to children, Thus you don’t need to exclusively write the same property for children if written for a parent already.

Compressing CSS File

Compression is usually done on the server side, which reduces CSS file size significantly without changing the content. Modern browsers have such capabilities to easily understand the compressed form of CSS versions.

Avoid the @import property

When you import a CSS file or font using the “@import” property, it will stop parsing the rest of the CSS and HTML, and first try to fetch the given CSS or font file, then only start processing the rest of the CSS and HTML file.

So it is recommended to avoid necessary importing multiple fonts as it can retrieve hundreds of kilobytes of font data. Also while fetching font, only load the weights and styles you require.

Avoid base64 bitmap images in CSS

Base64 encoded images in CSS should be avoided as they bulk up the CSS file size. This can lead to longer loading times, which can negatively impact user experience and search engine rankings. 

A better approach is to save the images as standalone files and reference them in the CSS using relative or absolute paths. This way, the CSS file remains lightweight, and images can be cached in the browser for faster subsequent page loads. Additionally, it is easier to maintain and update the images if they are separate files, rather than embedding them in the CSS.

Also Read, Simple steps to Increase your Website’s Web Performance

Final Words

Optimizing CSS is an essential task for improving website performance and user experience. It involves reducing file size, minimizing HTTP requests, and streamlining styles to improve load times and visual rendering. The best way to optimize CSS depends on various factors, such as the size of the CSS file, the complexity of styles, and the platform used. Some effective techniques include using CSS preprocessors, avoiding unnecessary CSS, compressing code, and leveraging browser caching. Ultimately, CSS optimization requires a combination of technical expertise, optimization tools, and ongoing monitoring to achieve the best results. By optimizing CSS, website owners can enhance website speed, engagement, and conversions, and improve search engine rankings.


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