Write a governance playbook in a {{tone}} tone for building and maintaining a dark mode design system in a legal organization. The playbook is for {{target_audience}} using Storybook and Vue.js, with the goal of improving customer satisfaction. Structure the playbook with these sections: Overview, Prerequisites, Step-by-step Plays (7 plays covering proposing components, modifying existing ones, quality standards, release and versioning, documentation, adoption and evangelism, roadmap planning), Metrics to Track, and Troubleshooting Guide. Maximum 800 words. Paste any relevant background information after these instructions before running.