Turns keyframe blocks — typed as CSS or chosen from presets (fade, slide, zoom, bounce, pulse, spin, shake, wobble, flip, heartbeat) — into a named @keyframes rule and an animation shorthand with duration, delay, timing function (keywords, Penner and Material presets, or your own cubic-bezier), iterations, direction and fill mode. A prefers-reduced-motion guard is included, and two-frame animations also get a transition equivalent. The preview runs the animation with pure CSS. Everything runs locally.