報稅季截止提醒海報（瑞士網格風）

prompt

Design an A2 portrait poster for {firm_name}, an accounting firm, reminding business clients about tax season. Style: strict Swiss International Typographic — visible modular grid, flat solid background in a single confident red or blue, oversized neo-grotesque sans-serif numerals showing {filing_deadline} as the dominant visual element, rotated 90-degree side text, and generous negative space. No photos or illustrations; communicate entirely through typography, alignment and one thin rule line. The lower-left grid cell carries a short message about {service_offer}; the lower-right carries {contact_line} in small caps. Asymmetric balance, flush-left ragged-right text, maximum two type sizes besides the numerals. Print-ready, portrait orientation.