Which CSS property controls font weight?

The CSS property that controls font weight is `font-weight`.

It sets how heavy or light text appears, using keywords such as `normal`, `bold`, `lighter`, and `bolder`, or numeric values such as 400 and 700. In the common numeric scale, 400 generally corresponds to normal text and 700 to bold text, although the exact appearance depends on the font family.

Font weight is part of CSS typography and can be declared directly in a rule, for example `font-weight: 600;`. Variable fonts may support a continuous range of weights rather than only a few predefined faces. If a requested weight is unavailable, the browser selects the closest available face according to its font-matching rules.

The neighboring properties are easy to confuse: `font-family` chooses the typeface, `font-size` controls text size, and `font-style` usually controls upright or italic presentation. The `font` shorthand can set weight along with family, size, style, and other font properties.