Can I use
?

system-ui value for font-family

- WD

Value for font-family that represents the default user interface font.

IE

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

Edge

  1. 12 - 18: Not supported
  2. 79 - 100: Supported
  3. 101: Supported

Firefox

  1. 2 - 42: Not supported
  2. 43 - 91: Partial support
  3. 92 - 99: Supported
  4. 100: Supported
  5. 101 - 102: Supported

Chrome

  1. 4 - 52: Not supported
  2. 53 - 55: Partial support
  3. 56 - 100: Supported
  4. 101: Supported
  5. 102 - 104: Supported

Safari

  1. 3.1 - 8: Not supported
  2. 9: Support unknown
  3. 9.1 - 10.1: Partial support
  4. 11 - 15.3: Supported
  5. 15.4: Supported
  6. TP: Supported

Opera

  1. 9 - 42: Not supported
  2. 43 - 85: Supported
  3. 86: Supported
  4. 87: Supported

Safari on iOS

  1. 3.2 - 8.4: Not supported
  2. 9 - 10.3: Partial support
  3. 11 - 15.3: Supported
  4. 15.4: Supported

Opera Mini

  1. all: Not supported

Android Browser

  1. 2.1 - 4.4.4: Not supported
  2. 101: Supported

Opera Mobile

  1. 10 - 12.1: Not supported
  2. 64: Supported

Chrome for Android

  1. 101: Supported

Firefox for Android

  1. 100: Supported

UC Browser for Android

  1. 12.12: Supported

Samsung Internet

  1. 4 - 5.4: Not supported
  2. 6.2 - 15.0: Supported
  3. 16.0: Supported

QQ Browser

  1. 10.4: Supported

Baidu Browser

  1. 7.12: Not supported

KaiOS Browser

  1. 2.5: Partial support
Resources:
Firefox support bug
MDN on the font-family property