Generate a product-introduction poster for [Product Name] in a "hand-drawn packaging pitch board" style. If I provide a product image, use it as the main reference, preserving the product's core appearance features, packaging form, colors, materials, brand identity and overall character, and prioritize the main color tones and color relationships from the product image in the design. If I do not provide a product image, automatically generate a product appearance and packaging design that fits the positioning of [Product Name], and automatically pair natural, reasonable main, secondary and background colors based on the product's attributes, category traits and character. Overall poster style requirements: This is not an ordinary e-commerce detail page, nor a plain studio-shot poster, but a creative pitch board fusing "finished product image + packaging design sketches + brand concept development process." The whole should read as a high-aesthetic, highly finished brand design showcase, as if a designer is presenting a packaging concept. Composition requirements: - Vertical composition - Use a unified, brand-feel main color tone background, with the background color decided naturally by the product itself, not fixed to any single color - The palette should harmonize with the product's attributes: with a reference image, prioritize inheriting its main color and brand color; without one, automatically generate a reasonable color scheme from the product name - Place a most complete, most eye-catching main product visual at the center, with real texture, three-dimensional light and shadow, and a commercial finished-product effect - Around the product, add multiple supporting visual elements: packaging sketches from different angles, structural sketches, local form explorations, small handheld-display studies, packaging unfolding ideas, brand wordmark typography experiments - Add natural, casual black or dark hand-drawn line work, arrows, circling marks, symbols and handwritten Chinese annotations, giving the image a strong "design process feel" and "creative pitch feel" - The finished image should be relatively refined and realistic, while the sketch parts should be relatively loose and lively, forming a contrast of "finished product + design sketch" - The layout should look relaxed and free, yet overall have order, rhythm and a visual center, reflecting high-end graphic design - You may moderately add small product-related graphics, symbols or playful elements to strengthen brand memorability - The final effect should have brand feel, creative feel, process feel and visual impact Color principles: - Do not fix a yellow background - Automatically choose the main tone based on the product's type, material, use, consumption feel and brand character - Background color, product color, text color and sketch line color should harmonize with one another - You may use a high-saturation monochrome background or a soft, unified color-family background, as long as the whole has brand feel and visual impact - Color should naturally serve the product rather than steal the spotlight Style keywords: packaging design pitch board, brand concept development, hand-drawn sketch, design process feel, moodboard, creative review proof, finished product render, visual experiment, commercial design poster Please note in particular: - With a reference product image, follow it as the priority and do not deviate from the product itself - Without a reference, automatically generate a reasonable product appearance, packaging and color scheme, keeping the overall style unified - The focus is "product introduction + creative design process showcase" - Do not make it an ordinary e-commerce detail page, do not make it a promotional poster, do not make it overly neat and rigid, do not lack sketches and handwritten annotations, avoid a cheap feel, avoid a childish cartoon feel