:root {
  color-scheme: light;
  --bg: #f8fafc;
  --card: #fff;
  --text: #0f172a;
  --muted: #64748b;
  --accent: #2563eb;
  --warn: #b45309;
  --border: #e2e8f0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--text); }
.banner {
  background: #fff7ed;
  border: 1px solid #fdba74;
  color: var(--warn);
  padding: 0.5rem 0.75rem;
  font-size: 0.75rem;
  font-weight: 600;
}
.shell { max-width: 560px; margin: 0 auto; padding: 1rem; }
.app-nav { display: flex; gap: 0.5rem; padding-top: 0.5rem; padding-bottom: 0; }
.nav-tab {
  flex: 1; text-align: center; padding: 0.65rem; border-radius: 10px 10px 0 0;
  text-decoration: none; color: var(--text); background: #e2e8f0; font-size: 0.85rem; font-weight: 600;
}
.nav-tab.active { background: var(--card); border: 1px solid var(--border); border-bottom-color: var(--card); }
.card { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 1rem; margin-bottom: 1rem; }
h1 { font-size: 1.25rem; margin: 0.5rem 0; }
h2 { font-size: 1rem; margin: 0 0 0.75rem; }
label { display: block; font-size: 0.8rem; color: var(--muted); margin-top: 0.5rem; }
input, textarea, select {
  width: 100%; padding: 0.55rem 0.65rem; border-radius: 8px; border: 1px solid var(--border);
  font-size: 1rem; background: #fff;
}
.row { display: grid; grid-template-columns: 1fr 1fr; gap: 0.5rem; }
.btn {
  display: inline-block; text-align: center; width: 100%; margin-top: 0.75rem;
  padding: 0.75rem; border-radius: 10px; background: var(--accent); color: #fff;
  text-decoration: none; border: none; font-size: 1rem; cursor: pointer;
}
.btn.secondary { background: #334155; }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }
.sig-pad { border: 1px dashed var(--border); border-radius: 8px; touch-action: none; background: #fff; width: 100%; height: 120px; }
.status { font-size: 0.9rem; padding: 0.75rem; border-radius: 8px; background: #eff6ff; }
.muted { color: var(--muted); font-size: 0.85rem; }
.checkline { display: flex; gap: 0.5rem; align-items: flex-start; margin: 0.75rem 0; font-size: 0.9rem; }
.copy-dialog { position: relative; border: 2px solid var(--accent); }
.copy-dialog input { margin-bottom: 0.5rem; }
@media (max-width: 480px) { .row { grid-template-columns: 1fr; } }