Can I use
?

CSS Generated content for pseudo-elements

- REC

Method of displaying text or images before or after the given element's contents using the ::before and ::after pseudo-elements. All browsers with support also support the attr() notation in the content property.

Chrome

  1. ✅ 4 - 134: Supported
  2. ✅ 135: Supported
  3. ✅ 136 - 138: Supported

Edge

  1. ✅ 12 - 134: Supported
  2. ✅ 135: Supported

Safari

  1. ✅ 3.1 - 18.3: Supported
  2. ✅ 18.4: Supported
  3. ✅ 18.5 - TP: Supported

Firefox

  1. ✅ 2 - 136: Supported
  2. ✅ 137: Supported
  3. ✅ 138 - 140: Supported

Opera

  1. ✅ 9 - 116: Supported
  2. ✅ 117: Supported

IE

  1. ❌ 5.5 - 7: Not supported
  2. ◐ 8: Partial support
  3. ✅ 9 - 10: Supported
  4. ✅ 11: Supported

Chrome for Android

  1. ✅ 135: Supported

Safari on iOS

  1. ✅ 3.2 - 18.3: Supported
  2. ✅ 18.4: Supported
  3. ✅ 18.5: Supported

Samsung Internet

  1. ✅ 4 - 26: Supported
  2. ✅ 27: Supported

Opera Mini

  1. ✅ all: Supported

Opera Mobile

  1. ✅ 10 - 12.1: Supported
  2. ✅ 80: Supported

UC Browser for Android

  1. ✅ 15.5: Supported

Android Browser

  1. ✅ 2.1 - 4.4.4: Supported
  2. ✅ 135: Supported

Firefox for Android

  1. ✅ 137: Supported

QQ Browser

  1. ✅ 14.9: Supported

Baidu Browser

  1. ✅ 13.52: Supported

KaiOS Browser

  1. ✅ 2.5: Supported
  2. ✅ 3: Supported

For content to appear in pseudo-elements, the content property must be set (but may be an empty string).

Resources:
Dev.Opera article
WebPlatform Docs
Guide on usage