The classic font pairing advice says: choose fonts that contrast. A serif display with a sans-serif body. This advice is not wrong ÔÇö but it is incomplete.
Mismatched x-Heights
Two fonts might look great in isolation but feel disconnected when used together. The culprit is often x-height ÔÇö the height of lowercase letters relative to capitals. When one font has a tall x-height and another has a small one, they feel like they come from different eras.
The Solution
The safest approach: pick one great typeface with multiple weights and use weight variation to create hierarchy. One typeface, used thoughtfully, almost always beats two fonts used carelessly.
