Zero‑Balance Digital Payment Card * margin: 0; padding: 0; box-sizing: border-box; body font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif; background: linear-gradient(145deg, #f0f4fa 0%, #e9f0f8 100%); padding: 20px; line-height: 1.5; color: #0b1a33;