Simple and clean flat design. Place figures and icons drawn with uniform black outline lines, using pastel accent colors partially. Unify the line thickness as much as possible to create a modern impression. Emphasize rounded shapes and a soft impression. Diagram-centric composition (e.g., Venn diagrams, bar graphs, speech bubbles) with a friendly tone suitable for materials viewed by students and young people, or for social media. Maximize white space, focusing on visibility and balanced design.