:root {
  --bg: #f2f2f2;
  --card: #ffffff;
  --ink: #000000;
  --muted: #555555;
  --border: #cccccc;
  --btn: #000000;
  --btn-text: #ffffff;
}
* { box-sizing: border-box; }
html, body {
  margin: 0; padding: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
  background: var(--bg); color: var(--ink);
  min-height: 100%;
}
header.appbar {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  padding: 0.75rem 1rem;
  display: flex; align-items: baseline; gap: 0.75rem; flex-wrap: wrap;
}
header.appbar h1 { margin: 0; font-size: 1.2rem; letter-spacing: 0.02em; }
header.appbar .tag { color: var(--muted); font-size: 0.8rem; }
main.layout {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 0.75rem;
  padding: 0.75rem;
  max-width: 1200px;
  margin: 0 auto;
}
@media (max-width: 800px) {
  main.layout { grid-template-columns: 1fr; }
}
.panel {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.9rem;
}
.panel label {
  display: block;
  font-size: 0.75rem;
  color: var(--muted);
  margin: 0.65rem 0 0.2rem;
}
.panel label:first-of-type { margin-top: 0; }
.panel select, .panel input[type="number"], .panel input[type="text"] {
  width: 100%;
  padding: 0.45rem 0.5rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 0.95rem;
  background: #fff;
  color: #000;
}
.panel button {
  cursor: pointer;
  width: 100%;
  margin-top: 0.5rem;
  border: 1px solid #000;
  border-radius: 8px;
  padding: 0.6rem 0.8rem;
  font-size: 0.92rem;
  font-weight: 600;
  background: var(--btn);
  color: var(--btn-text);
}
.panel button.ghost {
  background: #fff;
  color: #000;
}
.panel button:active { opacity: 0.85; }
.disclaimer {
  margin-top: 0.9rem;
  font-size: 0.72rem;
  color: var(--muted);
  line-height: 1.35;
  border-top: 1px solid var(--border);
  padding-top: 0.6rem;
}
.metrics {
  margin-top: 0.75rem;
  font-size: 0.82rem;
  line-height: 1.45;
  background: #f7f7f7;
  border-radius: 6px;
  padding: 0.55rem 0.65rem;
}
.sheet-wrap {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.6rem;
  overflow: auto;
}
#preview {
  background: #fff;
  border: 1px solid #ddd;
  aspect-ratio: 297 / 210;
  width: 100%;
  max-height: calc(100vh - 120px);
}
#preview svg { display: block; width: 100%; height: 100%; }
@media print {
  header.appbar, .panel { display: none !important; }
  main.layout { display: block; padding: 0; max-width: none; }
  .sheet-wrap { border: none; padding: 0; border-radius: 0; }
  #preview { border: none; max-height: none; width: 297mm; height: 210mm; }
  @page { size: A4 landscape; margin: 0; }
}