The quiet power of line-height
Most text that feels cramped is not too small. It is packed too tightly, and one number fixes it.
There is a moment in every project where someone says the text feels heavy. They usually reach for the font size. Nine times out of ten the size is fine and the leading is wrong.
Rhythm before size
Line-height is the interval that lets the eye find the next line without effort. Set it too tight and the reader keeps losing their place. Set it too loose and the paragraph stops behaving like a block of text at all.
A paragraph is not a list of lines. It is one shape, and leading is what gives it a silhouette.
A starting point
For body copy, begin around 1.6 and adjust down as the measure narrows. Headlines want far less, often 1.1, because their size already supplies the space. The larger the type, the tighter the leading.
Then read it aloud on a phone. The number that survives that test is the right one.
