A 10-second teaser video for CallBook, an app where traders seal price calls on chain and the price later decides if they hit.

MP4, 1280x720, 24 fps, exactly 10 seconds, silent, no voice-over.

Three scenes, about 3 seconds each, with quick smooth cuts:

1. Close-up: a hand presses a wax seal onto an envelope lying on a dark desk; a faint candlestick chart glows on a screen behind it.
2. A glowing price line on a dark chart climbs and touches a dotted horizontal target line; a mint-green (#3fcf7f) check mark flashes at the point where it touches.
3. A thick ledger closes; on its cover the word CALLBOOK appears in clean capital letters, then under it: Calls you can't delete. Hold this title for the last second. Style: cinematic, dark navy and charcoal with mint-green accents, no real company logos, no people's faces. Spell the on-screen text exactly as written.