Can I use
?

display: run-in

- CR

If the run-in box contains a block box, same as block. If a block box follows the run-in box, the run-in box becomes the first inline box of the block box. If an inline box follows, the run-in box becomes a block box.

Chrome

  1. ✅ 4 - 31: Supported
  2. ❌ 32 - 142: Not supported
  3. ❌ 143: Not supported
  4. ❌ 144 - 146: Not supported

Edge

  1. ❌ 12 - 142: Not supported
  2. ❌ 143: Not supported

Safari

  1. ✅ 3.1 - 4: Supported
  2. ✅ 5 - 6: Supported
  3. ﹖ 6.1: Support unknown
  4. ❌ 7 - 26.1: Not supported
  5. ❌ 26.2: Not supported
  6. ❌ 26.3 - TP: Not supported

Firefox

  1. ❌ 2 - 145: Not supported
  2. ❌ 146: Not supported
  3. ❌ 147 - 149: Not supported

Opera

  1. ✅ 9 - 18: Supported
  2. ❌ 19 - 124: Not supported
  3. ❌ 125: Not supported

IE

  1. ❌ 5.5 - 7: Not supported
  2. ✅ 8 - 10: Supported
  3. ✅ 11: Supported

Chrome for Android

  1. ❌ 143: Not supported

Safari on iOS

  1. ✅ 3.2: Supported
  2. ✅ 4 - 7.1: Supported
  3. ❌ 8 - 26.1: Not supported
  4. ❌ 26.2: Not supported
  5. ❌ 26.3: Not supported

Samsung Internet

  1. ❌ 4 - 28: Not supported
  2. ❌ 29: Not supported

Opera Mini

  1. ✅ all: Supported

Opera Mobile

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

UC Browser for Android

  1. ❌ 15.5: Not supported

Android Browser

  1. ✅ 2.1 - 4.4: Supported
  2. ❌ 4.4.3: Not supported
  3. ❌ 143: Not supported

Firefox for Android

  1. ❌ 146: Not supported

QQ Browser

  1. ❌ 14.9: Not supported

Baidu Browser

  1. ❌ 13.52: Not supported

KaiOS Browser

  1. ❌ 2.5: Not supported
  2. ❌ 3: Not supported
Resources:
Mozilla bug report
CSS Tricks article