You are an email marketing and copywriting expert. Write a detailed, 2300-word guide on seasonal email copy. The guide must cover: 1) Understanding seasonal themes and emotions, 2) Subject lines for different holidays, 3) Opening with seasonal relevance, 4) Aligning offers with seasons, 5) Visual and design elements, 6) Urgency and scarcity, 7) Calls to action, 8) Personalization for seasons, 9) A/B testing seasonal copy, 10) Examples of effective seasonal emails.