"OPEN STUDIO" は、予約不要の子ども向けアートの時間を知らせるフラットなイラストのポスターです。コーラル色の丸みのある大文字の下で、赤いエプロンの笑顔の女の子がイーゼルに黄色い花を描き、パレット、筆立て、緑の葉があり、下に青い "Saturday 10AM" の帯があります。見出し、キャッチコピー、曜日と時間、最後の一文を差し替えて、自分のワークショップ用に作り直せます。

Create a bright, finished square Instagram event post in a modern flat-cartoon vector illustration style. Use a warm cream background with a few simple coral, sky-blue, mint, and sunny-yellow organic shapes, tiny sparkles, and circles. Keep the palette to solid colour fills with crisp colour-against-colour edges, no heavy outlines, no gradients, no gloss, and only one soft darker shadow tone per shape. Add a faint hint of grain only in the background. Top-center, set the exact headline “OPEN STUDIO” in large, bold, friendly rounded sans-serif lettering with generous open counters and softly rounded terminals. Below it, in smaller uppercase rounded sans, set “PAINT · PLAY · BLOOM”. Keep all text clean, correctly spelled, and highly legible. Make the central illustration the visual hero: a cheerful original girl shown from the waist up, with a round face, dot eyes, a small curved smile, simple hair, and a brightly coloured apron. She is actively painting a large yellow flower on a small upright canvas; the flower has a bold round golden centre and broad sunny-yellow petals, clearly the biggest object in the illustration. Show her holding a paintbrush near the flower. Use simple solid shapes and friendly expressive body language, no anime features. Place the girl and canvas in the middle of the composition, framed by a few small palette-coloured leaves, dots, and sparkles. At the bottom, set “Saturday 10AM” as the clear event detail, then a smaller call to action “DROP IN & CREATE”. Center all text on one vertical axis, with comfortable separation between text and illustration. Bright, welcoming, playful, polished, and readable at phone-feed size. Include no other words or lettering.