Prompt: Design a still image background that transitions from color #400AC1 to #7D2FFF, tailored for a mobile journaling app. The gradient should be smooth and devoid of texture, resembling a clean, dusk-hued canvas occupying 70% of the space. Introduce subtle, vertical-diagonal waves or creases akin to the natural imperfections of paper. The overall feel should be one of elegance and depth, with a dark base that enhances the visibility of white text, while the gradient's lighter end offers a warm, inviting atmosphere.