Can I use
?

system-ui value for font-family

- WD

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

Chrome

  1. 4 - 52: Not supported
  2. 53 - 55: Partial support
  3. 56 - 107: Supported
  4. 108: Supported
  5. 109 - 111: Supported

Edge

  1. 12 - 18: Not supported
  2. 79 - 106: Supported
  3. 107: Supported

Safari

  1. 3.1 - 8: Not supported
  2. 9: Support unknown
  3. 9.1 - 10.1: Partial support
  4. 11 - 16.0: Supported
  5. 16.1: Supported
  6. 16.2 - TP: Supported

Firefox

  1. 2 - 42: Not supported
  2. 43 - 91: Partial support
  3. 92 - 106: Supported
  4. 107: Supported
  5. 108 - 109: Supported

Opera

  1. 9 - 42: Not supported
  2. 43 - 91: Supported
  3. 92: Supported

IE

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

Chrome for Android

  1. 107: Supported

Safari on iOS

  1. 3.2 - 8.4: Not supported
  2. 9 - 10.3: Partial support
  3. 11 - 16.0: Supported
  4. 16.1: Supported

Samsung Internet

  1. 4 - 5.4: Not supported
  2. 6.2 - 18.0: Supported
  3. 19.0: Supported

Opera Mini

  1. all: Not supported

Opera Mobile

  1. 10 - 12.1: Not supported
  2. 72: Supported

UC Browser for Android

  1. 13.4: Supported

Android Browser

  1. 2.1 - 4.4.4: Not supported
  2. 107: Supported

Firefox for Android

  1. 106: Supported

QQ Browser

  1. 13.1: Supported

Baidu Browser

  1. 13.18: Supported

KaiOS Browser

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