Minimal Wavy Lines with Soft Gradients for Phone Case Stickers

Create clean, vector-style illustrations featuring minimal wavy lines with subtle, soft gradients. Ensure a pure white background with high contrast, optimized for die-cut sticker formats. Designs should avoid shading and complex gradients, focusing on smooth, flowing lines that evoke a calm, modern aesthetic. Use [placeholder text] for customizable elements, maintaining a sleek, minimal feel suitable for high-quality phone case stickers.