Can I use
?

CSS Variables (Custom Properties)

- CR

Permits the declaration and usage of cascading variables in stylesheets.

Chrome

  1. ❌ 4 - 47: Not supported
  2. ❌ 48: Disabled by default
  3. ✅ 49 - 134: Supported
  4. ✅ 135: Supported
  5. ✅ 136 - 138: Supported

Edge

  1. ❌ 12 - 14: Not supported
  2. ◐ 15: Partial support
  3. ✅ 16 - 134: Supported
  4. ✅ 135: Supported

Safari

  1. ❌ 3.1 - 9: Not supported
  2. ◐ 9.1: Partial support
  3. ✅ 10 - 18.3: Supported
  4. ✅ 18.4: Supported
  5. ✅ 18.5 - TP: Supported

Firefox

  1. ❌ 2 - 30: Not supported
  2. ✅ 31 - 136: Supported
  3. ✅ 137: Supported
  4. ✅ 138 - 140: Supported

Opera

  1. ❌ 9 - 34: Not supported
  2. ❌ 35: Disabled by default
  3. ✅ 36 - 116: Supported
  4. ✅ 117: Supported

IE

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

Chrome for Android

  1. ✅ 135: Supported

Safari on iOS

  1. ❌ 3.2 - 9.2: Not supported
  2. ◐ 9.3: Partial support
  3. ✅ 10 - 18.3: Supported
  4. ✅ 18.4: Supported
  5. ✅ 18.5: Supported

Samsung Internet

  1. ❌ 4: Not supported
  2. ✅ 5 - 26: Supported
  3. ✅ 27: Supported

Opera Mini

  1. ❌ all: Not supported

Opera Mobile

  1. ❌ 10 - 12.1: Not supported
  2. ✅ 80: Supported

UC Browser for Android

  1. ✅ 15.5: Supported

Android Browser

  1. ❌ 2.1 - 4.4.4: Not 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
Resources:
Edge Dev Blog post
MDN Web Docs - Using CSS variables
Polyfill for IE11
Mozilla hacks article (older syntax)