:root {
  --bg: #0b0e14;
  --bg2: #11151d;
  --card: #151b26;
  --text: #eef1f6;
  --muted: #9aa3b2;
  --rainbow: linear-gradient(90deg, #ff5f6d, #ffc371, #f9f871, #7bf59b, #6ec6ff, #b388ff);
  --radius: 14px;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
}
a { color: inherit; }

/* Nav */
.nav {
  position: sticky; top: 0; z-index: 10;
  display: flex; align-items: center; gap: 1.5rem;
  padding: 0.8rem 1.5rem;
  background: rgba(11, 14, 20, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid #1e2532;
}
.brand { display: flex; align-items: center; gap: 0.6rem; text-decoration: none; font-weight: 800; font-size: 1.2rem; letter-spacing: 0.08em; }
.brand img { border-radius: 8px; height: auto; }
.nav nav { display: flex; gap: 1.2rem; margin-left: auto; }
.nav nav a.nav-link { text-decoration: none; color: var(--muted); font-weight: 600; }
.nav nav a.nav-link:hover { color: var(--text); }

/* Buttons */
.btn {
  display: inline-block; text-decoration: none; font-weight: 700;
  background: var(--rainbow); color: #0b0e14;
  border-radius: 999px; padding: 0.55rem 1.3rem;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}
.btn:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(255, 95, 109, 0.25); }
.btn-big { font-size: 1.1rem; padding: 0.9rem 2.2rem; }
.btn-small { font-size: 0.9rem; }
  .btn-solid { background: #eef1f6; color: #000; font-weight: 800; }
  .btn-solid:hover { box-shadow: 0 8px 24px rgba(238, 241, 246, 0.22); }

/* Hero */
.hero {
  text-align: center;
  padding: 5rem 1.5rem 4rem;
  background: radial-gradient(ellipse 60% 50% at 50% 0%, rgba(179, 136, 255, 0.12), transparent);
}
.hero-logo { width: 120px; height: auto; margin-bottom: 1rem;
  filter: drop-shadow(0 14px 34px rgba(0, 0, 0, 0.45)); }
.hero h1 {
  font-size: 4rem; letter-spacing: 0.12em; font-weight: 900;
  background: var(--rainbow);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.tagline { font-size: 1.3rem; color: var(--muted); margin-top: 0.3rem; }
.lede { max-width: 620px; margin: 1.2rem auto 0; font-size: 1.15rem; }
.cta-row { margin-top: 2rem; }
.fineprint { color: var(--muted); font-size: 0.9rem; margin-top: 1rem; }

/* Sections */
section { max-width: 960px; margin: 0 auto; padding: 3.5rem 1.5rem; }
section h2 { font-size: 2rem; margin-bottom: 0.6rem; }
.section-sub { color: var(--muted); margin-bottom: 1.8rem; font-size: 1.05rem; }
.about p { font-size: 1.1rem; color: #d4d9e2; max-width: 720px; }

/* Cards */
.cards {
  display: grid; gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
}
.card {
  background: var(--card);
  border: 1px solid #232c3d;
  border-radius: var(--radius);
  padding: 1.4rem;
}
.card h3 { font-size: 1.1rem; margin-bottom: 0.5rem; display: flex; align-items: center; gap: 0.5rem; }
.card h3 .pill { margin-left: 0; flex-shrink: 0; }
.card p { color: var(--muted); font-size: 0.97rem; }
.demo .cta-row, .ondra .cta-row { text-align: center; }

/* Ondra */
.pill {
  display: inline-block; white-space: nowrap;
  font-size: 0.8rem; font-weight: 700; vertical-align: middle;
  background: #fff; color: #0b0e14;
  border-radius: 999px; padding: 0.25rem 0.8rem; margin-left: 0.5rem;
  letter-spacing: 0.02em;
}
h2 .pill { background: var(--rainbow); }

/* FAQ */
.faq details {
  background: var(--card); border: 1px solid #232c3d;
  border-radius: var(--radius); padding: 1rem 1.3rem; margin-bottom: 0.8rem;
}
.faq summary { cursor: pointer; font-weight: 700; font-size: 1.05rem; }
.faq details p { color: var(--muted); margin-top: 0.6rem; }

/* Footer */
footer {
  text-align: center; padding: 2.5rem 1.5rem;
  border-top: 1px solid #1e2532; color: var(--muted);
}
footer p { margin-bottom: 0.4rem; }
footer a { color: var(--text); font-weight: 600; }

@media (max-width: 640px) {
  .nav { flex-wrap: wrap; gap: 0.7rem 1rem; padding: 0.8rem 1rem; }
  .nav nav { display: flex; order: 3; flex-basis: 100%; justify-content: center; gap: 0.6rem; margin-left: 0; }
  .hero h1 { font-size: 2.8rem; }
  .hero { padding: 3.5rem 1.2rem 3rem; }
}

/* Ondra O mark */
.o-mark { display: inline-block; vertical-align: -0.18em; }
.hero { position: relative; overflow: hidden; }
.o-watermark {
  position: absolute; left: 50%; top: 44%;
  width: min(560px, 130vw); opacity: 0.13;
  transform: translate(-50%, -50%);
  pointer-events: none;
}
.hero > :not(.o-watermark) { position: relative; }

/* Computer-only demo guard */
.computer-only-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.72);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  padding: 1.5rem;
}
.computer-only-box {
  background: #111827;
  color: #f9fafb;
  border: 1px solid #374151;
  border-radius: 12px;
  padding: 1.5rem 1.75rem;
  max-width: 24rem;
  text-align: center;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
}
.computer-only-box p {
  margin: 0 0 1rem;
  line-height: 1.5;
}
.computer-only-box button {
  background: #f9fafb;
  color: #111827;
  border: none;
  border-radius: 8px;
  padding: 0.6rem 1.6rem;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
}

/* Mobile: the header demo button is redundant next to the page buttons,
   so hide it and keep GCAI / Ondra / FAQ reachable. */
@media (max-width: 640px) {
  .nav > a.btn { display: none; }
}