@page{size:A4;margin:0}.arithmetic-cards-app *{margin:0;padding:0;box-sizing:border-box}.arithmetic-cards-app{font-family:Noto Sans SC,Microsoft YaHei,PingFang SC,sans-serif;-webkit-print-color-adjust:exact;print-color-adjust:exact}.arithmetic-cards-app .sheet{width:210mm;height:297mm;display:flex;flex-direction:column;position:relative;overflow:hidden;page-break-after:always;background:#fff}.arithmetic-cards-app .sheet:last-child{page-break-after:auto}.arithmetic-cards-app .sheet:before{content:"";position:absolute;inset:10mm;border:.2mm dashed rgba(99,102,241,.3);pointer-events:none;z-index:1}.arithmetic-cards-app .cut-line{position:absolute;pointer-events:none;z-index:1}.arithmetic-cards-app .cut-v{width:0;left:105mm;top:10mm;bottom:10mm;border-left:.15mm dashed rgba(148,163,184,.4)}.arithmetic-cards-app .cut-h{height:0;left:10mm;right:10mm;border-top:.15mm dashed rgba(148,163,184,.4)}.arithmetic-cards-app .grid{flex:1;display:grid;grid-template-columns:1fr 1fr;grid-template-rows:repeat(4,1fr)}.arithmetic-cards-app .card{padding:4mm 6mm;display:flex;flex-direction:column;align-items:center;justify-content:center;position:relative;overflow:hidden}.arithmetic-cards-app .card.add{background:linear-gradient(135deg,#eff6ff,#dbeafe)}.arithmetic-cards-app .card.add .badge{background:#3b82f6}.arithmetic-cards-app .card.add .method-name{background:#3b82f626;color:#1e40af}.arithmetic-cards-app .card.add .steps .arrow{color:#6366f1}.arithmetic-cards-app .card.add .decomp-svg .line{stroke:#6366f1}.arithmetic-cards-app .card.add .decomp-svg .brace-label{fill:#6366f1}.arithmetic-cards-app .card.sub{background:linear-gradient(135deg,#fff7ed,#fed7aa)}.arithmetic-cards-app .card.sub .badge{background:#f97316}.arithmetic-cards-app .card.sub .method-name{background:#f9731626;color:#9a3412}.arithmetic-cards-app .card.sub .steps .arrow{color:#ea580c}.arithmetic-cards-app .card.sub .decomp-svg .line{stroke:#ea580c}.arithmetic-cards-app .card.sub .decomp-svg .brace-label{fill:#ea580c}.arithmetic-cards-app .card-front .expression{font-size:16mm;font-weight:900;letter-spacing:1mm;color:#1e293b;text-align:center;line-height:1.2}.arithmetic-cards-app .card-front .badge,.arithmetic-cards-app .card-back .badge{position:absolute;top:3mm;left:3mm;color:#fff;font-weight:700;border-radius:2mm}.arithmetic-cards-app .card-front .badge{font-size:3.2mm;padding:.8mm 2mm}.arithmetic-cards-app .card-front .card-id{position:absolute;top:3mm;right:3mm;font-size:3mm;color:#64748b;font-weight:600}.arithmetic-cards-app .card-front .hint{margin-top:2mm;font-size:3mm;color:#94a3b8}.arithmetic-cards-app .card-back .badge{font-size:2.8mm;padding:.6mm 1.8mm}.arithmetic-cards-app .card-back .answer{position:absolute;top:3mm;right:3mm;font-size:3.5mm;font-weight:800;color:#1e293b}.arithmetic-cards-app .card-back .formula{font-size:5mm;font-weight:800;text-align:center;margin-bottom:2mm;color:#1e293b}.arithmetic-cards-app .card-back .method-name{font-size:3.2mm;font-weight:700;text-align:center;margin-bottom:2mm;padding:.5mm 0;border-radius:1.5mm}.arithmetic-cards-app .card-back .decomp-svg{width:100%;flex:1;min-height:22mm;display:flex;align-items:center;justify-content:center}.arithmetic-cards-app .card-back .steps{font-size:2.8mm;line-height:1.5;text-align:center;margin-top:1mm;color:#475569}.arithmetic-cards-app .card-back .steps .arrow{font-weight:700}.arithmetic-cards-app .decomp-svg text{font-family:Noto Sans SC,Microsoft YaHei,sans-serif;font-weight:700}.arithmetic-cards-app .decomp-svg .num-big{font-size:5mm}.arithmetic-cards-app .decomp-svg .num-small{font-size:3.5mm;fill:#64748b}.arithmetic-cards-app .decomp-svg .num-result{font-size:4.5mm;fill:#059669;font-weight:900}.arithmetic-cards-app .decomp-svg .op{font-size:3.5mm;fill:#94a3b8}.arithmetic-cards-app .decomp-svg .line{stroke-width:.5;fill:none}.arithmetic-cards-app .decomp-svg .brace-label{font-size:3mm;font-weight:700}.arithmetic-cards-app .sheet-label{position:absolute;bottom:3mm;left:50%;transform:translate(-50%);font-size:2.5mm;color:#cbd5e1;z-index:2;letter-spacing:.5mm}@media screen{.arithmetic-cards-app{background:#e2e8f0;padding:20px}.arithmetic-cards-app .sheet{margin:0 auto 20px;box-shadow:0 4px 24px #00000026}}