:root {
  --ink: #0f172a;
  --muted: #5b6472;
  --brand: #3730a3;     /* indigo */
  --brand-2: #4f46e5;
  --accent: #f59e0b;
  --bg: #f8fafc;
  --card: #ffffff;
  --line: #e5e7eb;
  --radius: 14px;
  --maxw: 880px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
a { color: var(--brand-2); }

/* nav */
.nav {
  display: flex; align-items: center; justify-content: space-between;
  max-width: var(--maxw); margin: 0 auto; padding: 18px 20px;
}
.brand { font-weight: 800; font-size: 22px; letter-spacing: -.02em; }
.brand .ai { color: var(--accent); }
.nav-links { display: flex; align-items: center; gap: 18px; }
.nav-links a { color: var(--muted); text-decoration: none; font-weight: 600; font-size: 14px; }
.nav-links a:hover { color: var(--ink); }
.lang button {
  border: 1px solid var(--line); background: #fff; color: var(--muted);
  border-radius: 8px; padding: 4px 9px; font-weight: 700; font-size: 12px; cursor: pointer;
}
.lang button.on { background: var(--brand); color: #fff; border-color: var(--brand); }

/* hero */
.hero { max-width: var(--maxw); margin: 24px auto 8px; padding: 0 20px; text-align: center; }
.hero h1 { font-size: clamp(28px, 5vw, 44px); line-height: 1.1; letter-spacing: -.03em; margin: 18px 0 10px; }
.hero .sub { color: var(--muted); font-size: 18px; max-width: 620px; margin: 0 auto; }

/* ask */
.ask { max-width: var(--maxw); margin: 28px auto; padding: 22px; background: var(--card);
  border: 1px solid var(--line); border-radius: var(--radius); box-shadow: 0 1px 3px rgba(15,23,42,.05); }
.ask-label { display: block; font-weight: 700; margin-bottom: 8px; }
#q { width: 100%; padding: 12px 14px; border: 1px solid var(--line); border-radius: 10px;
  font: inherit; resize: vertical; }
#q:focus { outline: none; border-color: var(--brand-2); box-shadow: 0 0 0 3px rgba(79,70,229,.15); }
.btn { margin-top: 12px; background: var(--brand); color: #fff; border: 0; border-radius: 10px;
  padding: 12px 22px; font-weight: 700; font-size: 15px; cursor: pointer; }
.btn:hover { background: var(--brand-2); }
.btn:disabled { opacity: .6; cursor: progress; }
.status { margin-top: 14px; color: var(--muted); }
.answer { margin-top: 16px; padding: 16px; background: #f1f5ff; border-radius: 10px; white-space: normal; }
.sources { margin-top: 14px; }
.sources h3 { font-size: 13px; text-transform: uppercase; letter-spacing: .04em; color: var(--muted); margin: 0 0 6px; }
.sources ul { margin: 0; padding-left: 18px; }
.sources li { margin: 3px 0; }
.disclaimer { margin-top: 16px; font-size: 12.5px; color: var(--muted); border-top: 1px solid var(--line); padding-top: 12px; }

/* pricing */
.pricing { max-width: var(--maxw); margin: 40px auto; padding: 0 20px; text-align: center; }
.pricing h2 { font-size: 26px; margin-bottom: 18px; }
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; }
.card.featured { border-color: var(--brand); box-shadow: 0 6px 24px rgba(55,48,163,.12); transform: translateY(-4px); }
.card h3 { margin: 0 0 6px; }
.card .price { font-size: 28px; font-weight: 800; margin: 0 0 8px; }
.card .price span { font-size: 14px; font-weight: 600; color: var(--muted); }
.card p:last-child { color: var(--muted); font-size: 14px; margin: 0; }

/* footer */
.footer { max-width: var(--maxw); margin: 30px auto; padding: 22px 20px; border-top: 1px solid var(--line);
  text-align: center; color: var(--muted); font-size: 13px; }
.footer .sister a { font-weight: 700; text-decoration: none; }
.footer .attr { margin-top: 6px; font-size: 12px; }

[hidden] { display: none !important; }

@media (max-width: 640px) {
  .cards { grid-template-columns: 1fr; }
  .card.featured { transform: none; }
  .nav-links { gap: 12px; }
}