PostCSS Dark Theme Class

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src="https://postcss.org/logo-leftp.svg">

CSS solution for light/dark/auto theme switcher for websites.

* It doesn’t have [FART] flash of light theme during JS initialization.
* Pure CSS solution. You need JS only to set HTML class, when user.
* Automatic theme provide better UX for users with theme switching
by subset/sunrise (all operating systems now have theme switching schedule).

[PostCSS] plugin to make switcher to force dark or light theme by copying styles
from media query or [light-dark()] to special class.

[PostCSS]: https://github.com/postcss/postcss
[FART]: https://css-tricks.com/flash-of-inaccurate-color-theme-fart/
[light-dark()]: https://developer.mozilla.org/en-US/docs/Web/CSS/color_value/light-dark

``css
/ Input CSS /

@media (prefers-color-scheme: dark) {
html {
--text-color: white
}
body {
background: black
}
}

section {
background: light-dark(white, black);
}
`

`css
/ Output CSS /

@media (prefers-color-scheme: dark) {
html:where(:not(.is-light)) {
--text-color: white
}
:where(html:not(.is-light)) body {
background: black
}
}
html:where(.is-dark) {
--text-color: white
}
:where(html.is-dark) body {
background: black
}

@media (prefers-color-scheme: dark) {
:where(html:not(.is-light)) section {
background: black;
}
}
:where(html.is-dark) section {
background: black;
}
@media (prefers-color-scheme: light) {
:where(html:not(.is-dark)) section {
background: white;
}
}
:where(html.is-light) section {
background: white;
}
`

By default (without classes on html), website will use browser dark/light
theme. If user want to use dark theme, you set html.is-dark class.
If user want to force light theme, you use html.is-light`.

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Docs

Read full docs here.