Create an original square Korean voucher campaign poster in purple, lavender, white, and gold, with a clear prize box, large voucher value, and a compact button. Text: “특별 사은 이벤트”, “10만원 바우처 증정”, “50,000원 x 2”, “회원 전용 혜택”, “지금 구매하기”. Use only two small stars and balanced geometric accents. Keep all visible text in Korean. No brand, watermark, QR code, website, Chinese text, English text, or random tiny text.