Research and Documentation Module 02

ChatGPT

"Research and Document the concept of CSS nesting. Discuss the origins of CSS nesting. Discuss the use of the ampersand as nesting selector. Discuss browser support based on data from the caniuse.com website." ChatGPT, GPT-3.5, OpenAI, 03 Apr. 2024, ai-url.com/chat.

The AI engine returned the following response:

Concept of CSS Nesting:
CSS nesting is a feature that allows CSS selectors to be nested within one another, creating a hierarchical structure to target specific elements within their parent elements. This feature provides a cleaner and more organized way to write CSS, especially when styling complex HTML
With CSS nesting, you can write selectors that mimic the structure of your HTML, making your CSS more intuitive and easier to maintain. It helps avoid repetition and increases code readability.
Origins of CSS Nesting: The concept of CSS nesting has evolved over time, but it gained significant attention with the introduction of CSS preprocessors like Sass (Syntactically Awesome Stylesheets). Sass introduced a syntax that allowed for nesting selectors, which was later adopted into CSS itself through various proposals and drafts in the CSS Working Group.
Use of the Ampersand (&) as a Nesting Selector:
In CSS preprocessors like Sass, the ampersand (&) is used as a placeholder for the parent selector. When nested within another selector, the ampersand represents the parent selector. This allows for more dynamic and contextual styling.
For example, in Sass:
.btn {
background-color: blue;
&:hover {
background-color: red;
}
}
In the above example, & represents .btn, so &:hover compiles to .btn:hover. Browser Support:
Browser support for CSS nesting, particularly using the & selector, has been gradually improving. As of my last update in January 2022, support for CSS nesting using preprocessors like Sass is widespread, but support for native CSS nesting using the & selector directly in CSS is still limited. According to data from caniuse.com:
Native CSS nesting with the & selector has partial support across modern browsers, with some support in major browsers like Chrome, Firefox, Safari, and Edge, but with varying degrees of implementation and prefixed versions. Internet Explorer does not support native CSS nesting. It's important to check the latest browser compatibility data on caniuse.com or similar platforms for the most up-to-date information regarding CSS nesting support in browsers. Additionally, using CSS preprocessors like Sass can provide broader support by compiling nested CSS into standard CSS that is compatible with a wider range of browsers.

From me

The block that you are reading is an example of CSS nesting. In the card class I nested another class named yellow that styles this particular card like legal paper with a yellow paper and blue lines.

The card class originally looked like this:
.card {
display: flex;
flex-direction: column;
border: 10px solid c.$theme-color-transparent;
padding: 1rem;
background-color: transparent;
border-radius: 1.5em;
box-shadow: 0 2px 3px rgba(0, 0, 0, 0.1);
margin: 10px auto;
}

I added this:
&.yellow {
background-image: repeating-linear-gradient(c.$paper-yellow 0px, c.$paper-yellow 24px, teal
25px);
}

The & is used as a nesting selector. It represents the parent selector. So what I wrote above "&.yellow" compiles as .card.yellow. in the browser. And subsequently anywhere that yellow class is added inside a card the styling changes. If the .yellow class is used outside of a card class it has no effect. For example if I remove the .card class from the div you're looking at there would be no styling applied at all because .yellow only exists as a child of the card class.

If I had a large block of content written in a tag, and I wanted to style a specific word or phrase a different color I could wrap the word or phrase in a and nest styling for the span inside a class that styles . This used to be accomplished right in the HTML using the font tag ie . This method has been deprecated in IE5 however, and may or may not work in modern browsers. To accomplish the red text in the tag above I used the following nested CSS code.
p {
color: inherit;
& span {
color: red;
}

I don't know if you noticed that "From me" is styled blue. That too is wrapped in a tag but the CSS code styles that tag differently because it's nested inside an <h2> tag. That same effect could be accomplished by creating a class and assigning it to the tag (which is how I styled the highlighted code snippets). I don't know that one is any easier than the other.

As far as how I would use nesting in a project goes, I think the biggest benefit of nesting is the organization of code. By nesting styles inside of styles you can keep your code more concise and readable. If I have a span inside a container inside a container and I want to style the span differently than the parent container, or the grandparent I can do that with nesting instead of having to write multiple classes.