A Guide to Use CSS for Search Engine Optimization

Tati Khumairoh

Published at April 05, 2024 01:29 AM

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    Using CSS for SEO is well-known for increasing the fast-loading of web pages. However, there are other reasons why webmasters should know the CSS SEO strategy.

    Every line of code, including bloated, inefficient CSS, affects the page load time. That is why using clean, optimized CSS practices like minification and compression can reduce file size and could mean faster page loading.

    In this article, we will guide you on how to use CSS for SEO with the hope that it can improve your overall site's performance. Let's begin the exploration here.

    What Is CSS?

    Before going deeper, let’s go for a refresher and understand the basics. So, CSS stands for Cascading Style Sheets. It is a style sheet language used for describing the look and formatting of a document written in a markup language, such as HTML or XML.

    CSS allows web developers to control the visual presentation of a web page, including aspects like layout, colors, fonts, and spacing.

    Key concepts in CSS include selectors, which target specific HTML elements, and declarations, which define the styles for those elements.

    CSS can be applied inline within HTML tags, in a separate external style sheet file, or internally within the HTML document using the <style> element.

    Benefits of CSS for SEO

    CSS can positively impact SEO in several ways. When web pages use well-organized and clean CSS, search engines can more easily understand the structure and content of the page. To know more about the benefits, here are some of the significant ones:

    1. Website Accessibility

    Accessibility is a crucial aspect of web development, this includes ensuring that websites are usable by people of all abilities and disabilities. In this case, CSS plays a role in enhancing accessibility by allowing developers to create flexible and responsive designs.

    CSS can also be used to adjust the layout and styling based on different screen sizes, making websites more accessible to users with various devices, such as smartphones, tablets, and desktop computers.

    Additionally, CSS can be utilized to improve the readability and navigation of web pages for users with visual impairments.

    2. Increase Download Speed

    CSS contributes to faster download speeds by reducing the amount of code that needs to be transmitted from the server to the user's device.

    External style sheets can be cached by the browser, meaning that once a user visits a website, the CSS file can be stored locally.

    Subsequent visits to the same site result in faster load times because the browser doesn't need to download the CSS again.

    Moreover, CSS allows for the implementation of techniques like minification and compression, which further reduce file sizes and enhance overall website performance.

    3. Cross-Browser Compatibility

    One of the challenges in web development is ensuring that websites look and function consistently across different web browsers, and CSS plays a crucial role in achieving that compatibility.

    It allows developers to write styles that are interpreted consistently by various browsers to ensure a uniform appearance and behavior. By using CSS, developers can create a more reliable and consistent user experience across popular browsers, like Chrome, Firefox, and Safari.

    How to Use CSS for Better SEO

    While CSS itself doesn't have a direct impact on SEO, the way you structure and use CSS can indirectly influence your site's SEO by affecting factors like page load speed and user experience. Here are some tips on how to use CSS for better SEO:

    1. Minimize CSS Code

    Remove unnecessary or redundant code from your CSS files. This practice not only reduces file size but also improves readability and maintainability.

    You can use tools like CSS minifiers to automatically eliminate whitespace, comments, and other non-essential elements. As a result, you can improve page load times which can enhance the user experience and lower bounce rates.

    2. Use External Stylesheet

    Next, use an external stylesheet. By placing your CSS code in external files and linking them to your HTML documents, you allow browsers to cache these stylesheets.

    Caching means that once a user visits your site, their browser can store the CSS file locally. Therefore, when a user visits multiple pages on your site, the stylesheet is likely already downloaded and stored locally.

    This caching behavior can positively affect the overall performance and user experience.

    3. Make Responsive Design

    The next CSS SEO you need to do is make a responsive design. Use CSS media queries to make your website responsive to different screen sizes. A responsive design ensures that your website adapts seamlessly to various screen sizes and devices.

    Not to mention, Google prioritizes mobile-friendly websites and responsive design contributes to better rankings on search engine results pages (SERPs).

    4. Optimize Images with CSS

    Employ CSS properties like background-size to optimize images. For example, using background-size: cover; ensures that a background image covers the entire container, preventing unnecessary image scaling and reducing the overall page load time.

    Here is an example of optimizing a background image using CSS

    .header {

    background-image: url('header-image.jpg');

    background-size: cover;


    Using CSS to optimize images, such as with background-size: cover;, ensures that images are appropriately sized and don't slow down page loading. This optimization can contribute to a faster-loading website, improving both user satisfaction and SEO rankings.

    5. Use Semantic HTML

    Semantic HTML involves using HTML tags that convey the meaning of their content. For example, using <header>, <nav>, and <article> tags instead of generic <div> tags.

    Semantic HTML enhances the understandability of your content for both users and search engines. Search engine bots can better interpret the structure and relevance of your content, potentially leading to improved rankings.

    6. Optimize Font Icons and Web Fonts

    While font icons and web fonts can enhance the design, be mindful of their impact on page load times. Use only the necessary icons or characters and consider techniques like icon fonts or SVG to optimize their delivery.

    Using font icons and web fonts judiciously can enhance visual appeal without significantly impacting page load times. As a result, it can contribute to a positive user experience, indirectly influencing SEO rankings.

    7. Write Readable and Maintainable Code

    Write CSS code that is easy to read and maintain. This not only helps other developers who may work on your code but also contributes to better crawlability by search engine bots.

    A well-organized code structure makes it clear how different elements on your page are styled.

    In summary, these CSS practices collectively contribute to a website's performance, user experience, and adherence to SEO best practices. Implementing these CSS SEO can result in faster-loading pages, improved mobile-friendliness, and a more favorable perception by search engines.

    Conducting Site Audits for CSS SEO

    After applying all the above strategies, you can conduct a site audit as part of CSS SEO. Conducting a comprehensive site audit that includes an analysis of CSS can help identify and address potential issues that might impact your website's performance and SEO.

    Here are some site audit issues to check regarding CSS SEO:

    1. Broken CSS

    Broken CSS refers to errors within the CSS code that prevent it from being properly interpreted and applied by the browser. This issue could result from syntax errors, missing or incorrect declarations, or references to non-existent resources.

    Solution: Validate your CSS code using tools like W3C CSS Validator to identify and fix syntax errors. Then, ensure that all referenced resources (images, fonts, etc.) are accessible.

    2. CSS File Size Too Large

    A CSS file that is excessively large can contribute to slow page load times. This issue could result from including unnecessary styles, large images, or not optimizing the CSS code.

    Solution: Minify and compress CSS files to reduce their size. Consider optimizing and prioritizing critical styles for above-the-fold content.

    3. CSS Redirect

    A CSS redirect occurs when the browser is instructed to follow a redirect to load the CSS file. This can happen if the CSS file is hosted on a different domain or if there are server-side redirects in place.

    Solution: Ensure that the CSS file is directly accessible without unnecessary redirects. You can use absolute URLs or consider hosting CSS files on the same domain to avoid cross-origin redirects.

    4. HTTPS Page Links to HTTP CSS

    If your website is served over HTTPS (secure), but the CSS file is linked with an HTTP URL, it can result in mixed content issues. Modern browsers may block the insecure resources that can lead to visual and security issues.

    Solution: Update the CSS file references to use HTTPS URLs to ensure a secure connection. Additionally, Ensure that all resources (CSS, images, scripts) are served securely when your website is accessed via HTTPS.

    You can use Sequence Stats Site Audit to inspect the above issues in detail. This tool offers comprehensive site audit results that are integrated with Lighthouse. Therefore, there is no need to inspect issues manually.

    Register now to try the Site Audit feature and other sophisticated features in Sequence Stats!