+
+Pigment CSS is MUI's new in-house styling solution: a zero-runtime CSS-in-JS package that generates colocated styles to their own CSS files at build-time.
+With Pigment CSS you get the latest and greatest advancements in CSS along with RSC compatibility, _plus_ significant performance improvements when compared with Emotion, the styling engine used in Material UI v5.
+And though we're prioritizing the needs of Material UI users in early development, Pigment CSS can be used with _any_ React component library you prefer.
+
+## Why Pigment CSS?
+
+### Traditional CSS-in-JS is not enough
+
+Emotion made a lot of sense for Material UI v5 in late 2021, but so much has changed in the React ecosystem since then.
+After Next.js offered the first implementation of the React Server Components spec with [the App Router](https://nextjs.org/blog/next-13) towards the end of 2022, it became clear that there was a monumental shift on the horizon.
+
+RSCs unlock a whole new realm of possibilities for React; for us as UI developers, it means we can create components that are fully renderable at build-time so we don't have to pass that burden on to the client at run-time.
+But working with RSCs requires us to let go of familiar APIs like `useContext`, which in turn becomes a major blocker for using the last generation's style engines like Emotion that rely heavily on this hook for theming.
+
+:::info
+To learn more about RSCs, we highly recommend reading [Making Sense of React Server Components](https://www.joshwcomeau.com/react/server-components/) by Josh Comeau.
+:::
+
+### Material UI is a unique use case
+
+Material UI is downloaded millions of times per month and is one of the most rigorously battle-tested UI libraries on the internet, with a GitHub history spanning all the way back to 2014.
+It's had to make some massive changes along the way to keep up with the times; most recently, moving from JSS to Emotion from v4 to v5.
+While those breaking changes did bring many benefits overall, they unfortunately came with a notoriously painful migration experience.
+
+We learned our lesson!
+We can't do that to our users again.
+
+So when it came time to seek out a new way to generate styles, we knew we needed to keep the syntax and authoring experience as similar as possible to Emotion and styled-components—and provide codemods for most of the breaking changes—in order to minimize friction when migrating.
+
+### Other options don't meet our needs
+
+For those of us who are perfectly happy with the patterns we know and love from CSS-in-JS, it feels frustrating to consider abandoning all that muscle memory just to reinvent the wheel yet again.
+We like the DX of colocated styles, and we'd rather not bloat the DOM with atomic class names—so Tailwind CSS, StyleX, Panda CSS, and other solutions that have cropped up in recent months just don't match up with our preferences.
+
+## How Pigment CSS works
+
+Pigment CSS is a zero-runtime CSS-in-JS library: This means it doesn't have access to the end user's browser runtime, which would be necessary to generate and insert authored CSS at run-time.
+Instead, it does all its processing at build-time to pre-generate the CSS which then becomes part of the output bundle.
+
+Pigment CSS is built on top of the [WyW-in-JS](https://wyw-in-js.dev/) library that also powers [Linaria](https://linaria.dev/).
+It features a [processor](https://wyw-in-js.dev/how-to/custom-tagged-template#creating-a-processor) which makes it possible to create custom logic that's triggered by the presence of different imports from the library.
+The processor looks through the source code for `styled()`, `css()`, and other function calls and extracts the arguments to be evaluated.
+These values are then handed back to Pigment CSS for additional parsing and evaluation.
+
+:::info
+Check out [How Pigment CSS works](https://github.com/mui/pigment-css/blob/master/HOW_PIGMENT_CSS_WORKS.md) for complete details.
+:::
+
+## Benefits of using Pigment CSS
+
+For users of Emotion and styled-components, the benefits of adopting Pigment CSS are clear: your end users get better performance, and you get RSC and App Router compatibility without having to significantly change how you author component styles.
+
+### Better performance
+
+When comparing the same Material UI app built with Next.js and either Emotion or Pigment CSS, we've observed the following results:
+
+| Metrics | Emotion | Pigment CSS | Reduction |
+| :--------------------- | ------: | ----------: | --------: |
+| First load JavaScript | 131kB | 104kB | 20% |
+| First Contentful Paint | 503ms | 455ms | 9% |
+| Time To First Byte | 447.5ms | 381.5ms | 15% |
+| Total Page HTML | 15.9kB | 14.7kB | 7.5% |
+
+:::info
+Curious about where those performance numbers came from?
+[Check out this app](https://pigment-css-demo.vercel.app/perf) that compares Pigment CSS, Emotion, and styled-components across a variety of tests.
+:::
+
+### Familiar developer experience
+
+For developers migrating from Emotion or styled-components, you're probably already familiar with the most common patterns employed by Pigment CSS.
+`styled()` and `css()` are the two main functions used to define styles, and they mostly work the same as you'd expect them to (with some notable differences due to the nature of build-time CSS-in-JS—see [Coming from Emotion or styled-components](https://github.com/mui/pigment-css/tree/master?tab=readme-ov-file#coming-from-emotion-or-styled-components) for details).
+
+```jsx
+import { styled, css } from '@pigment-css/react';
+
+const Title = styled('h1') ({
+ fontSize: '2rem';
+});
+
+const Container = styled.div`
+ border: 1px solid red;
+
+ &:hover {
+ border-color: blue;
+ }
+
+ ${Title} {
+ margin-bottom: 2.5rem;
+ }
+`;
+
+export default function Modal() {
+ return (
+ World
++ Pigment CSS offers significant performance gains along with RSC +
+