:root{--bg:#0f1115;--card:#171a21;--fg:#e8eaf0;--muted:#9aa3b2;--accent:#4f8cff;--line:#2a2f3a;--good:#2ecc71}
*{box-sizing:border-box}
body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;background:var(--bg);color:var(--fg)}
.top{padding:24px 20px;border-bottom:1px solid var(--line)}
.brand{font-size:22px;font-weight:700}
.tag{color:var(--muted);font-size:13px;margin-top:4px}
.layout{display:grid;grid-template-columns:1fr 1fr;gap:24px;padding:24px;max-width:1280px;margin:0 auto}
@media(max-width:900px){.layout{grid-template-columns:1fr}}
.form,.preview{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:20px}
h2{margin:0 0 12px;font-size:18px}
h3{margin:16px 0 8px;font-size:15px;color:var(--muted)}
.row{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:12px;margin-bottom:12px}
label{display:flex;flex-direction:column;font-size:12px;color:var(--muted);gap:4px}
input,select,textarea{background:#0f1115;color:var(--fg);border:1px solid var(--line);border-radius:8px;padding:8px 10px;font-size:14px}
input:focus,select:focus,textarea:focus{outline:none;border-color:var(--accent)}
.items{margin-bottom:12px}
.item-row{display:grid;grid-template-columns:2fr 80px 120px 40px;gap:8px;margin-bottom:8px;align-items:center}
.item-row input{width:100%}
.rm{background:transparent;border:1px solid var(--line);color:var(--muted);border-radius:6px;cursor:pointer;padding:6px}
.actions{display:flex;flex-wrap:wrap;gap:8px;margin-top:16px}
.btn{border:1px solid var(--line);background:#0f1115;color:var(--fg);padding:10px 14px;border-radius:8px;cursor:pointer;font-size:14px}
.btn.primary{background:var(--accent);border-color:var(--accent);color:#fff}
.btn.secondary{background:#1f2430}
.btn.ghost{background:transparent}
.hint{color:var(--muted);font-size:12px;margin-top:8px}

.invoice{background:#fff;color:#111;padding:32px;border-radius:8px}
.inv-head{display:flex;justify-content:space-between;align-items:flex-start;margin-bottom:24px}
.inv-title{font-size:28px;font-weight:800;letter-spacing:1px}
.inv-no{color:#555;font-size:13px;margin-top:4px}
.inv-meta{font-size:13px;text-align:right}
.inv-meta span{color:#777}
.parties{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin-bottom:24px}
.label{font-size:11px;text-transform:uppercase;color:#777;letter-spacing:.5px;margin-bottom:4px}
.name{font-weight:600;font-size:15px}
.email{font-size:13px;color:#555}
.items{width:100%;border-collapse:collapse;margin-bottom:16px}
.items th,.items td{padding:8px;border-bottom:1px solid #ddd;font-size:13px}
.items th{text-align:left;background:#f5f5f5}
.items td:nth-child(2),.items td:nth-child(3),.items td:nth-child(4){text-align:right}
.total-label{text-align:right;font-weight:700}
.total-val{text-align:right;font-weight:700;font-size:16px}
.payment{background:#f5f5f5;padding:12px;border-radius:6px;margin-bottom:12px;font-size:13px}
.payment code{word-break:break-all;font-size:12px}
.paid{margin-top:8px;color:#1e7e34}
.badge{background:#2ecc71;color:#fff;padding:2px 8px;border-radius:4px;font-size:11px;font-weight:700;margin-right:6px}
.notes{font-size:13px;color:#444;margin-bottom:12px;white-space:pre-wrap}
.footer{font-size:11px;color:#999;border-top:1px solid #ddd;padding-top:8px;margin-top:8px}

@media print{
  body{background:#fff}
  .top,.form{display:none}
  .layout{padding:0;max-width:none}
  .preview{border:none;background:#fff;padding:0}
  .invoice{box-shadow:none}
}
PY
echo written