Can I use
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ch (character) unit

- CR

Unit representing the width of the character "0" in the current font, of particular use in combination with monospace fonts.

Chrome

  1. ❌ 4 - 26: Not supported
  2. ✅ 27 - 130: Supported
  3. ✅ 131: Supported
  4. ✅ 132 - 134: Supported

Edge

  1. ✅ 12 - 130: Supported
  2. ✅ 131: Supported

Safari

  1. ❌ 3.1 - 6.1: Not supported
  2. ✅ 7 - 18.0: Supported
  3. ✅ 18.1: Supported
  4. ✅ 18.2 - TP: Supported

Firefox

  1. ✅ 2 - 131: Supported
  2. ✅ 132: Supported
  3. ✅ 133 - 135: Supported

Opera

  1. ❌ 9 - 12.1: Not supported
  2. ✅ 15 - 113: Supported
  3. ✅ 114: Supported

IE

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

Chrome for Android

  1. ✅ 131: Supported

Safari on iOS

  1. ❌ 3.2 - 6.1: Not supported
  2. ✅ 7 - 18.0: Supported
  3. ✅ 18.1: Supported
  4. ✅ 18.2: Supported

Samsung Internet

  1. ✅ 4 - 25: Supported
  2. ✅ 26: 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 - 4.3: Not supported
  2. ✅ 4.4 - 4.4.4: Supported
  3. ✅ 131: Supported

Firefox for Android

  1. ✅ 132: Supported

QQ Browser

  1. ✅ 14.9: Supported

Baidu Browser

  1. ✅ 13.52: Supported

KaiOS Browser

  1. ✅ 2.5: Supported
  2. ✅ 3: Supported
Resources:
Blog post on using ch units
What is the CSS ‘ch’ Unit?