What Is CSS? The Ultimate Learning Guide to Success

What is CSS and how to learn CSS for free online

Along with HTML and JavaScript, CSS is one of the three primary pillars of web technology, making it an equally crucial component of programming. However, not everyone knows what the abbreviation stands for and how to use it properly. Understanding CSS is essential to climbing up the career ladder in web development, whether creating more visually appealing web pages or improving the overall user experience. 

Continue reading to find out more about CSS use cases, the advantages and disadvantages of CSS, as well as about applying HTML to CSS.

A developer sitting in front of the laptop and coding

Key Terms Defined: What Is CSS?

CSS stands for Cascading Style Sheets. Simply put, CSS is a design language that enhances a website’s visual appeal beyond plain or uninteresting text. While HTML essentially controls the text content, CSS controls the visual structure, layout, and aesthetics. HTML is a markup language, whereas CSS is a language for creating style sheets. Inline CSS, internal or embedded CSS, and external CSS are the three categories under which CSS is categorized.

To be clear, CSS is used by 96.9% of all websites. If we go back to history, W3C (World Wide Web Consortium) created CSS because the HTML element needed to be developed to have tags that would help customize the page. Only the markup for the web page could be written with HTML.

HTML version 3.2 introduced tags like <font>, which caused many problems for web developers. Because web pages have different fonts, colored backgrounds, and styles, rewriting the code was a time-consuming, painful, and expensive process. As a result, the W3C developed CSS to address this issue.

Even though HTML and CSS are relatively old programming languages, their usage is still relevant for developers. In terms of programming languages used by software developers globally as of 2022, JavaScript and HTML/CSS accounted for more than 65% and slightly over 55%, respectively.

Loading Webpages Created with CSS

A browser must combine the content of a document with its style information when displaying it. It goes through the document in a series of stages, which are listed below. 

Note: This is a simplified interpretation of what happens when a browser loads a webpage and that different browsers will run the process differently. However, this will assist you in understanding what happens:

  1. The browser loads the HTML.
  2. It transforms HTML into a DOM (Document Object Model). In the computer’s memory, the DOM represents the document.
  3. The browser then retrieves the majority of the resources linked to by the HTML document, including embedded images, videos, and even linked CSS.
  4. The browser parses the fetched CSS and sorts the different rules into “buckets” based on their selector types. It determines which rules should be applied to which DOM nodes and applies the style to them as needed.
  5. The render tree is laid out in the structure it will have after the rules have been applied.
Coding examples and CSS use cases

CSS Use Cases

A web browser is instructed to display a particular webpage using CSS. It can style HTML elements but cannot be used to add new page elements.

CSS is a language describing how web pages look, including their colors, design, and fonts. It enables the presentation to be adapted to different devices, such as large screens, small screens, or printers.

Here are some popular websites that were built using CSS:

  • Google.com
  • Youtube.com
  • Facebook.com
  • Netflix.com
  • Instagram.com
  • Twitter.com
  • Wikipedia.org

CSS Advantages and Disadvantages

Knowing the advantages and disadvantages of CSS as a language, you’ll understand better where to use CSS once you have mastered this language.

CSS Advantages

  1. Page Speed Increase

CSS allows you to write less code. This results in applying a single CSS rule to all occurrences of a specific tag within an HTML document.

  1. Improved User Experience

CSS not only makes web pages more visually appealing, but it also allows for user-friendly formatting.

  1. Shorter Development Time

A cascading style sheet can be used on multiple website pages.

  1. Simple Formatting Modifications

If you want to change the format of a specific set of pages, simply edit the corresponding CSS stylesheet, and the changes will be applied to all pages that use that style sheet.

  1. Device-to-Device Compatibility

CSS and HTML work together to enable responsive design on mobile, tablet, desktop, and even smart TV devices.

Code examples for CSS

CSS Disadvantages

Yet, CSS has a few disadvantages to keep in mind when learning it as a tool for development. Here are a few of them:

  1. The Confusion Caused by Multiple CSS Levels

Beginners are more susceptible to this problem. They may become perplexed if they learn CSS because there are various levels of CSS, such as CSS2, CSS3, and so on.

  1. Problems with Cross-Browser Navigation

Different browsers operate in different ways. As a result, you must ensure that changes made to the website via CSS codes are properly reflected across all browsers.

  1. Security Concerns

Security is critical today, which is dominated by technology and data. CSS has limited security, which is one of its major drawbacks.

  1. Additional Work for Developers

Design services must consider and test all CSS codes for compatibility across multiple browsers. Developers’ workload increases as they test compatibility for various browsers.

Applying CSS to HTML

First, consider three approaches to applying CSS to a document: external stylesheets, internal stylesheets, and inline styles.

External stylesheet

CSS is contained in a separate file with the .css extension in an external stylesheet. This is the most common and useful way to add CSS to a document. A single CSS file can be linked to multiple web pages, styling them all with the same CSS stylesheet.

Internal stylesheet

An HTML document contains an internal stylesheet. To make one, include CSS in a <style> element within the HTML <head>.

Internal stylesheets can be useful in some situations. Perhaps you’re working with a content management system that prevents you from modifying external CSS files.

However, using an internal stylesheet for sites with more than one page becomes less efficient. To use internal stylesheets to apply uniform CSS styling to multiple pages, you must have one on each web page that will use the styling.

Inline styles

CSS declarations that affect a single HTML element and are contained within a style attribute are known as inline styles.

It’s obvious that today the external stylesheet will be used more frequently when possible. But when it’s not, the other two options will come to help.

The Easiest and The Quickest Way to Learn CSS

Acquiring new skills requires a lot of resources. You dedicate much time, energy, and effort to learning something new. This is especially relevant when learning to code. Time and effort are not the only essential things for beginners. A relevant, trustworthy and helpful resource is the best investment you can make to master coding.

WildLearner’s CSS course is intended for absolute beginners: you don’t need any background to start the course. With 33 lessons divided into 6 parts, this course is written in easy-to-read and explicit language. So you will not face any inconvenience when studying. It will only take 4 hours of learning – that’s it! Here are the parts of the CSS course from WildLearner:

  • Basics
  • Styling
  • Box Model
  • Effects
  • Layout
  • Responsive

WildLearner courses are free of charge: you never pay for learning, and you get a free certificate when you finish the course. Need help? It’s not a problem with WildLearner. You will meet the most supportive team of developers who will help you with sound advice. Place your question and wait for the answers.

Besides CSS, WildLearner has many online courses, such as JavaScript, HTML, Node.js, Vue.js, MongoDB, Python, etc. All of them are free of charge, so after completing your course, you can continue with other languages and their libraries that may interest you. Acquire a new skill and get a free certificate when you finish the course.

Moreover, at WildLearner, you can get valuable knowledge by just reading the blog posts on the website. Whether it’s about career development or technical blog posts about coding, you will get useful insights in the end.


Although you may face some difficulties while learning CSS, believe us, it’s totally worth your effort. Choose a trustworthy and comprehensive course, dedicate some time and attention and you will master a new skill. Learning CSS is not enough to become an experienced developer. Yet, it’s the quality foundation you will need in the future. No preparations are needed: start learning CSS with WildLearner today.


F: What is the difference between HTML and CSS?

A: HTML is a markup language, whereas CSS is a language for creating style sheets.

F: What types does the CSS have?

A: There are three types of CSS: External CSS, Internal CSS, and Inline CSS.

F: Where is CSS used?

A: CSS is used to instruct a web browser on how to display a specific website. It can style HTML elements but cannot be used to add new page elements.