Both were previously unimplemented and silently dropped. text-underline-offset moves the line further from (or closer to) the text; text-underline-position chooses where it starts from before that offset is applied.
| auto (default) | Hamburgefonstiv |
| offset: 6px | Hamburgefonstiv |
| offset: -2px | Hamburgefonstiv |
| offset: 25% | Hamburgefonstiv |
| position: from-font | Hamburgefonstiv |
| position: under | Hamburgefonstiv gjpqy |