| CARVIEW |
Select Language
HTTP/2 200
x-guploader-uploadid: AAwnv3IFQVjZpZylh3_MUF_E1IVdVDoMtMk0CQSyR3N7pbDnpJi-WNvkcmEcpXJza1LbTY3s
x-goog-generation: 1760058704312471
x-goog-metageneration: 1
x-goog-stored-content-encoding: identity
x-goog-stored-content-length: 270370
x-goog-meta-goog-reserved-file-mtime: 1760056722
x-goog-hash: crc32c=DKifWg==, md5=IblLfl1PKPHeZ3OjXvCTZA==
x-goog-storage-class: STANDARD
accept-ranges: none
expires: Sun, 12 Oct 2025 01:39:21 GMT
cache-control: public, max-age=3600
last-modified: Fri, 10 Oct 2025 01:11:44 GMT
etag: W/"21b94b7e5d4f28f1de6773a35ef09364"
content-type: text/html
age: 0
alt-svc: h3=":443"; ma=2592000,h3-29=":443"; ma=2592000
alt-svc: clear
referrer-policy: strict-origin-when-cross-origin
x-content-type-options: nosniff
strict-transport-security: max-age=63072000
content-security-policy: default-src 'self'; script-src 'report-sample' 'self' 'wasm-unsafe-eval' https://www.google-analytics.com/analytics.js https://www.googletagmanager.com/gtag/js assets.codepen.io production-assets.codepen.io https://js.stripe.com 'sha256-XNBp89FG76amD8BqrJzyflxOF9PaWPqPqvJfKZPCv7M=' 'sha256-YCNoU9DNiinACbd8n6UPyB/8vj0kXvhkOni9/06SuYw=' 'sha256-PZjP7OR6mBEtnvXIZfCZ5PuOlxoDF1LDZL8aj8c42rw='; script-src-elem 'report-sample' 'self' 'wasm-unsafe-eval' https://www.google-analytics.com/analytics.js https://www.googletagmanager.com/gtag/js assets.codepen.io production-assets.codepen.io https://js.stripe.com 'sha256-XNBp89FG76amD8BqrJzyflxOF9PaWPqPqvJfKZPCv7M=' 'sha256-YCNoU9DNiinACbd8n6UPyB/8vj0kXvhkOni9/06SuYw=' 'sha256-PZjP7OR6mBEtnvXIZfCZ5PuOlxoDF1LDZL8aj8c42rw='; style-src 'report-sample' 'self' 'unsafe-inline'; object-src 'none'; base-uri 'self'; connect-src 'self' developer.allizom.org bcd.developer.allizom.org bcd.developer.mozilla.org updates.developer.allizom.org updates.developer.mozilla.org https://*.google-analytics.com https://*.analytics.google.com https://*.googletagmanager.com https://incoming.telemetry.mozilla.org https://observatory-api.mdn.allizom.net https://observatory-api.mdn.mozilla.net https://api.github.com/search/issues stats.g.doubleclick.net https://api.stripe.com; font-src 'self'; frame-src 'self' interactive-examples.mdn.mozilla.net interactive-examples.mdn.allizom.net mdn.github.io live-samples.mdn.mozilla.net live-samples.mdn.allizom.net *.mdnplay.dev *.mdnyalp.dev *.play.test.mdn.allizom.net https://v2.scrimba.com https://scrimba.com jsfiddle.net www.youtube-nocookie.com codepen.io survey.alchemer.com https://js.stripe.com; img-src 'self' data: *.githubusercontent.com *.googleusercontent.com *.gravatar.com mozillausercontent.com firefoxusercontent.com profile.stage.mozaws.net profile.accounts.firefox.com developer.mozilla.org mdn.dev interactive-examples.mdn.mozilla.net interactive-examples.mdn.allizom.net wikipedia.org upload.wikimedia.org https://mdn.github.io/shared-assets/ https://mdn.dev/ https://*.google-analytics.com https://*.googletagmanager.com www.gstatic.com; manifest-src 'self'; media-src 'self' archive.org videos.cdn.mozilla.net https://mdn.github.io/shared-assets/; child-src 'self'; worker-src 'self';
x-frame-options: DENY
origin-trial: AxVILwizhbMjxFeHOn1P3R8niO1RJY/smaK4B4d1rLzc1gTaxtXMSaTi+FoigYgCw40uFRDwFcEAeqDR+vVLOW4AAABfeyJvcmlnaW4iOiJodHRwczovL2RldmVsb3Blci5tb3ppbGxhLm9yZyIsImZlYXR1cmUiOiJQcml2YXRlQXR0cmlidXRpb25WMiIsImV4cGlyeSI6MTc0MjA3OTYwMH0=
x-cloud-trace-context: f9cc15154cfda84082e1b0d42118bda7
date: Sun, 12 Oct 2025 00:39:21 GMT
server: Google Frontend
via: 1.1 google
vary: Accept-Encoding
content-encoding: gzip
x-cache: miss
:root - CSS: カスケーディングスタイルシート | MDN
Toggle sidebar
このページはコミュニティーの尽力で英語から翻訳されました。MDN Web Docs コミュニティーについてもっと知り、仲間になるにはこちらから。
:root
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since 2015年7月.
:root は CSS の擬似クラスで、文書を表すツリーのルート要素を選択します。 HTML では :root は <html> 要素を表し、詳細度が高いことを除けば html セレクターと同等です。
css
/* 文書のルート要素（HTML の場合は <html>）を選択 */
:root {
background: yellow;
}
構文
:root
例
グローバルの CSS 変数
:root はグローバルの CSS 変数を宣言するのに便利です。
css
:root {
--main-color: hotpink;
--pane-padding: 5px 42px;
}
仕様書
| Specification |
|---|
| Selectors Level 4 # root-pseudo |
ブラウザーの互換性
Loading…