What is the difference between shorthand and longhand CSS properties?

Shorthand CSS properties allow you to set multiple related properties at once, while longhand properties define each individual property separately. For example, margin: 10px 20px is shorthand for setting all four margins, whereas margin-top, margin-right, margin-bottom, and margin-left are longhand properties. Shorthand properties make your code more compact and efficient, but longhand gives you more control over individual values.