IntroductionWhat is CSS nesting?Why use CSS nesting?Browser support for CSS nestingCSS Selectors RefresherNesting BasicsNesting selectorsThe ampersandNesting pseudo-classesCommon Nesting PatternsNested media queriesBest PracticesConclusion Introduction CSS nesting allows you to nest CSS selectors within other selectors. This can help keep your CSS neat and organized.

What is CSS nesting? CSS nesting is a feature that allows you to nest CSS selectors within other CSS selectors to create a relationship between the nested selectors. For example, you can nest a class selector within an element selector:

nav { background: blue; .menu-item { color: white; } } The .menu-item selector is nested inside the nav selector. This means the styling for .menu-item will only apply to menu items that are inside the element.

Why use CSS nesting? Nesting can help organize your CSS and make it easier to read. It allows you to group related styles together. Nesting also lets you be more concise – you don’t have to repeat parent selectors.

Browser support for CSS nesting Native CSS nesting is supported in most modern browsers, including Chrome, Firefox, Safari, and Edge. However, IE11 and earlier do not support it. Preprocessors like Sass and LESS provide nesting capabilities and can compile to browser-compatible CSS.

CSS Selectors Refresher Before diving into nesting syntax, let’s recap some CSS selector basics:

Type selectors – Target elements by element name, like h1, div, etc.

Class selectors – Target elements by class name, denoted with a . prefix, like .menu.

ID selectors – Target elements by ID, denoted with a # prefix, like #navbar.

Attribute selectors – Target elements by attribute, like [type=”text”].

Pseudo-class selectors – Target elements based on state, like :hover or :active.

Nesting Basics Nesting selectors To nest a selector, simply put it inside the declaration block of the parent selector:

main { /* main styles */ .box { /* box styles */ } } This nests the .box selector inside main. The .box styles will only apply to boxes inside .

The ampersand You can use the ampersand (&) to reference the parent selector from within a nested ruleset.

For example:

main { .box { &:hover { /* styles for hovered .box inside main*/ } } } Nesting pseudo-classes You can nest pseudo-classes like :hover, :active, etc. This is useful for state-based styles:

button { /* button styles */ &:hover { /* button hover styles */ } &:active { /* button active styles */ } } This nests the hover and active pseudo-classes inside button.

Common Nesting Patterns Nested media queries Media queries can be nested inside other selectors:

“`css
.container {
/* styles */

@media (max-width: 600px) {
/* styles for screens combinator: css
ul {
/* ul styles */

li {
/* styles for li children */
}
}
“`

Best Practices Limit depth of nesting – Try to avoid nesting selectors more than 3 levels deep, as overly nested CSS can get hard to read. Use Sass/LESS nesting carefully – If using a CSS preprocessor like Sass or LESS, be careful with nesting everything just because you can. Nest thoughtfully. Nest for succinctness, not just because you can – Only nest when it makes your code more concise by avoiding repetition. Don’t nest just for the sake of nesting. Conclusion Nesting your CSS selects helps keep related styles together. It takes some practice to use effectively, but can make your CSS more organized, readable and reusable. Start simple and work your way up to more complex nesting as you get comfortable with the syntax.