Can I use
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Shadow DOM (deprecated V0 spec)

- UNOFF

Original V0 version of the Shadow DOM specification. See Shadow DOM V1 for support for the latest version.

IE

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

Edge

  1. 12 - 18: Not supported
  2. 79: Supported
  3. 80 - 85: Not supported
  4. 86: Not supported

Firefox

  1. 2 - 28: Not supported
  2. 29 - 60: Disabled by default
  3. 61 - 80: Not supported
  4. 81: Not supported
  5. 82 - 83: Not supported

Chrome

  1. 4 - 24: Not supported
  2. 25 - 34: Supported
  3. 35 - 79: Supported
  4. 80 - 85: Not supported
  5. 86: Not supported
  6. 87 - 89: Not supported

Safari

  1. 3.1 - 13.1: Not supported
  2. 14: Not supported
  3. TP: Not supported

Opera

  1. 9 - 12.1: Not supported
  2. 15 - 21: Supported
  3. 22 - 66: Supported
  4. 67 - 70: Not supported
  5. 71: Not supported

iOS Safari

  1. 3.2 - 13.7: Not supported
  2. 14: Not supported

Opera Mini

  1. all: Not supported

Android Browser

  1. 2.1 - 4.3: Not supported
  2. 4.4 - 4.4.4: Supported
  3. 81: Not supported

Blackberry Browser

  1. 7: Not supported
  2. 10: Not supported

Opera Mobile

  1. 10 - 12.1: Not supported
  2. 59: Supported

Chrome for Android

  1. 85: Not supported

Firefox for Android

  1. 79: Not supported

IE Mobile

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

UC Browser for Android

  1. 12.12: Supported

Samsung Internet

  1. 4: Supported
  2. 5 - 11.2: Supported
  3. 12.0: Supported

QQ Browser

  1. 10.4: Supported

Baidu Browser

  1. 7.12: Supported

KaiOS Browser

  1. 2.5: Supported
Resources:
Shadow DOM Visualizer
Safari implementation bug
Firefox implementation bug
Google Developers - Shadow DOM v1: self-contained web components
HTML5Rocks - Shadow DOM 101 article