In this Hasty Treat, Scott and Wes talk about CSS nesting — what it is, when to use it, and why.
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Show Notes
04:22 - What is it?
06:02 - Why nest?
- Easier to read
- Easier to write
- Prevents refactoring errors, allows for dry-er code. No more typing a parent div 100 times, with a possibility of screwing it up.
08:13 - When to use nesting
- Nesting is often overused
- Only nest what you would have written un-nested with a short hand (e.g. don’t nest just for the sake of it)
- .container .item {} .container .item a {}
- Use it for scoping
10:06 - Nesting prefixes
- In order to nest CSS, you must first start it with a nesting selector
.tweet { & > p { } &.media-included { color: green; } & + .tweet { } // sibling & p { } // descentang }
- Component-based — tweet, card, company, Link
article{ color: blue; & { color: red; } }
and must be the first child of a compound selector
12:44 - @nest rule / media queries
- Mostly just a visual way to show nested
.foo { display: grid; @media(orientation: landscape) { & { grid-auto-flow: column; } } }
.foo { display: grid; @media (orientation: landscape) { & { grid-auto-flow: column; } @media (min-inline-size > 1024px) { & { max-inline-size: 1024px; } } } } /* equivalent to .foo { display: grid; } @media (orientation: landscape) { .foo { grid-auto-flow: column; } } @media (orientation: landscape) and (min-inline-size > 1024px) { .foo { max-inline-size: 1024px; } } */
16:30 - How to use nesting today
- Literally any CSS preprocessor
- PostCSS to use spec
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