capitalization after a colon
Whether the first word after a colon takes a capital.
If what follows the colon is not a complete sentence, use lowercase: Bring three things: nails, twine, and a lamp. If what follows is a complete sentence, a capital is acceptable: The rule was simple: No one leaves early. Many writers still use lowercase there. Do not capitalize a list of fragments after a colon.
Examples
UseHe wanted one thing: time.
UseThe note was blunt: Leave the key.
AvoidBring three things: Nails, twine, and a lamp.