Prompt: Create a still image that mimics a dark blue, ink-stained paper background, transitioning smoothly from a rich indigo to a warm midnight blue for a journaling app interface. The background should be dark, featuring a barely-there texture that suggests the fine quality of journal paper, with one or two understated, vertical-diagonal creases, as if influenced by the flow of ink. Ensure the gradient is predominantly dark to allow for legibility of white text, invoking a sense of warmth and depth appropriate for a luxury journaling experience.