Type foundations

The vocabulary and measurement system everything else depends on. Most typographic mistakes at the decision level trace back to a wrong model here.

1. When to invoke

• A term needs defining before a decision can be made.
• Someone conflates font/typeface, leading/line-height, or point/pixel.
• Choosing CSS units for type.
• Explaining a typographic decision to a developer or client.

Do not invoke when the decision is already scoped — go to the specific skill.

2. Required context

• The medium — print units and screen units are related but not equivalent.
• The audience's existing vocabulary, so you correct only what matters.