Craft a tranquil coloring page for adults in the zen doodle style, characterized by simplicity and mindful design. Depict a serene woman seated on a gentle hill, taking in the beauty of nature. The woman's posture should exude calmness, and her gaze should be directed towards a breathtaking sunset that paints the sky in warm hues. Embrace simplicity by using minimal lines and patterns to capture the essence of the scene. The woman's features and clothing can be defined through subtle yet graceful strokes. The hill can be represented with gentle curving lines, offering a sense of elevation and repose. Ensure that the design adheres to a black and white color scheme, with intricate patterns forming the landscape, sunset, and the woman's presence. Maintain a white background to keep the coloring page airy and inviting. Create a balance between detailing and open spaces, allowing for a peaceful coloring experience that avoids overwhelming intricacy.