The em dash is a versatile punctuation mark. Depending on the context, it can take the place of commas, parentheses, or colons⁠. Like commas and parentheses, em dashes can set off extra information, such as examples, explanatory or descriptive phrases, or additional details:

Every element of a design — typography, colors, etc. — carries a visual weight.

Or like a colon, an em dash can introduce a clause that explains or expands upon something that precedes it:

All users agreed — the design looked amazing.