Develop a 12-month seasonal marketing calendar for our <product/service> that capitalises on relevant holidays, events, and trends. Identify key seasons and moments that align with our brand and audience interests. Create themes, campaign concepts, and promotional ideas for each major season or event. Outline content strategies and channel-specific tactics for each period. Propose ways to balance evergreen marketing efforts with timely, seasonal activations. Finally, recommend planning and execution timelines, along with metrics to measure the impact of seasonal marketing efforts on overall business goals.