Can I use
?

Scoped CSS

- UNOFF

Deprecated method of allowing scoped CSS styles using a "scoped" attribute. Now removed from the specification and replaced by the @scope CSS rule.

Chrome

  1. 4 - 19: Not supported
  2. 20 - 36: Disabled by default
  3. 37 - 116: Not supported
  4. 117: Not supported
  5. 118 - 120: Not supported

Edge

  1. 12 - 116: Not supported
  2. 117: Not supported

Safari

  1. 3.1 - 16.5: Not supported
  2. 16.6: Not supported
  3. 17.0 - TP: Not supported

Firefox

  1. 2 - 20: Not supported
  2. 21 - 54: Supported
  3. 55 - 60: Disabled by default
  4. 61 - 116: Not supported
  5. 117: Not supported
  6. 118 - 120: Not supported

Opera

  1. 9 - 101: Not supported
  2. 102: Not supported

IE

  1. 5.5 - 10: Not supported
  2. 11: Not supported

Chrome for Android

  1. 117: Not supported

Safari on iOS

  1. 3.2 - 16.6: Not supported
  2. 17.0: Not supported
  3. 17.1: Not supported

Samsung Internet

  1. 4 - 21: Not supported
  2. 22: Not supported

Opera Mini

  1. all: Not supported

Opera Mobile

  1. 10 - 12.1: Not supported
  2. 73: Not supported

UC Browser for Android

  1. 15.5: Not supported

Android Browser

  1. 2.1 - 4.4.4: Not supported
  2. 117: Not supported

Firefox for Android

  1. 117: Not supported

QQ Browser

  1. 13.1: Not supported

Baidu Browser

  1. 13.18: Not supported

KaiOS Browser

  1. 2.5: Supported
  2. 3: Not supported
Resources:
Firefox bug #1291515: disable `<style scoped>` in content documents
HTML5Rocks article
Polyfill
HTML5 Doctor article