A friendly, historically inspired Yunmenglong dinosaur in line art for a children's coloring book. Show a giant, long-necked sauropod with a gentle face, long tail, thick pillar-like legs, and subtle body texture (like folds or muscles) for visual interest. Friendly, non-scary expression, standing or walking in a calm pose. Line art only, no color filled in, no background, bold and clear outlines suitable for easy coloring by kids.