Q. When writing technical documentation, some steps may require a warning or information of note with the step. In those instances, the information begins either with “Warning:” or “Note:” (respectively). If the word before the colon is bolded, should the colon also be bolded?
A. In the scenario you describe, the colon belongs to the word it’s next to rather than to the words that follow. If the former is in a bold font—or in italics or a different color—then the colon would be styled to match:
Warning: Don’t press this button.
Note: Some buttons are more important than others.
See CMOS 6.2 and 6.3 for some additional considerations and examples.