/* --- Layout base --- */
:root {
  --bg: #f5f6fa;
  --fg: #1f2937;
  --card: #ffffff;
  --muted: #6b7280;
  --primary: #4f46e5;
  --chip: #eef2ff;
  --chip-text: #3730a3;
  --ring: rgba(79,70,229,.25);
  /* baseline tipografia */
  --text-size: 16px;
  --lh: 1.75;
  --row: calc(var(--text-size) * var(--lh));
  --paper: radial-gradient(circle at 10% 10%, rgba(0,0,0,0.04), transparent 40%),
           radial-gradient(circle at 90% 0, rgba(0,0,0,0.03), transparent 30%),
           linear-gradient(#ffffff, #fbfbfd);
  --paper-line: rgba(59,130,246,0.25);
  --paper-margin: rgba(239,68,68,0.3);
}

[data-theme="dark"] {
  --bg: #0b1020;
  --fg: #e5e7eb;
  --card: #0f172a;
  --muted: #94a3b8;
  --primary: #8b5cf6;
  --chip: #1f2937;
  --chip-text: #e5e7eb;
  --ring: rgba(139,92,246,.35);
  --paper: radial-gradient(circle at 10% 10%, rgba(255,255,255,0.04), transparent 40%),
           radial-gradient(circle at 90% 0, rgba(255,255,255,0.03), transparent 30%),
           linear-gradient(#0b1220, #0b1220);
  --paper-line: rgba(56,189,248,0.15);
  --paper-margin: rgba(248,113,113,0.18);
}

[data-theme="sepia"] {
  --bg: #f6f1e7;
  --fg: #3b2f2f;
  --card: #fbf6ec;
  --muted: #7c6a5a;
  --primary: #a16207;
  --chip: #f1e7d6;
  --chip-text: #7c3e00;
  --ring: rgba(161,98,7,.25);
  --paper: linear-gradient(#fbf6ec, #f9f1df);
  --paper-line: rgba(161,98,7,0.25);
  --paper-margin: rgba(190,18,60,0.22);
}
* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--fg);
}
.visually-hidden { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }
.hidden { display: none; }
.muted { color: var(--muted); }
.fade-in { animation: fade .22s ease; }
@keyframes fade { from { opacity: .55; transform: translateY(4px);} to { opacity: 1; transform:none;} }