Gorgeous 2D cel anime teaser trailer, hand-painted backgrounds, fluid sakuga animation. Opening: extreme wide of a sky-blue morning over an archipelago of floating islands strung with rope bridges, a girl on a winged bicycle bursting out of a cloudbank with a satchel of glowing letters, cel highlights flaring; a bright string-and-flute theme lifts over rushing wind. Cut to: dynamic sakuga sequence — she dives through a canyon of waterfalls, pedaling hard, letters streaming light behind her like a comet tail, linework stretching loose with the speed; taiko drums kick in, paper flutters snapping like sails. Cut to: quiet beat — she lands on a tiny island where an old man waits beside a red postbox and hands him a single envelope, both silhouetted against an enormous setting sun, petals drifting; the music drops to a lone piano and the hush of evening insects. Final shot: night — hundreds of delivered letters rise off the islands as lanterns of light, spiraling upward to redraw the constellations while she watches from her bike mid-air, eyes shining; full orchestral swell with choir, hard cut to black on a single bicycle-bell ring. Vivid cel-painted palette with warm sunset golds and sky cyans, subtle animation-cel grain, painterly volumetric light, ultra-detailed backgrounds, dynamic confident camera movement, trailer pacing, no text, no captions, no watermark.