:root {
  --bg-base: #0f1115;
  --bg-card: #1a1d24;
  --bg-elevated: #262830;
  --border: #363840;
  --border-subtle: #2a2c34;
  --text-primary: #f0f0f2;
  --text-secondary: #9ca3af;
  --text-tertiary: #9ca3af;
  --accent: #ffff00;
  --accent-muted: rgba(255, 255, 0, 0.12);
  --display: "Orbitron", ui-sans-serif, system-ui, sans-serif;
  --body: "Inter", ui-sans-serif, system-ui, sans-serif;
}
* { box-sizing: border-box; }
html, body {
  margin: 0; padding: 0;
  background: var(--bg-base); color: var(--text-primary);
  font-family: var(--body); font-size: 15px; line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); }
.wrap { max-width: 960px; margin: 0 auto; padding: 0 20px; }
@media (min-width: 640px) { .wrap { padding: 0 32px; } }

/* Top bar */
.bar {
  position: sticky; top: 0; z-index: 40;
  background: rgba(15, 17, 21, 0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-subtle);
}
.bar-inner {
  max-width: 1200px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 20px;
}
@media (min-width: 640px) { .bar-inner { padding: 14px 32px; } }
.brand {
  font-family: var(--display); font-weight: 900; font-size: 14px;
  letter-spacing: 0.04em; color: var(--text-primary); text-decoration: none;
}
.brand .yellow { color: var(--accent); }
.topnav {
  display: flex; align-items: center; gap: 4px; font-size: 14px;
}
.topnav a.link, .topnav .current {
  padding: 8px 12px; border-radius: 6px;
  text-decoration: none; font-weight: 500;
}
.topnav a.link { color: var(--text-secondary); }
.topnav a.link:hover { background: var(--bg-elevated); color: var(--text-primary); }
.topnav .current { color: var(--accent); }
@media (max-width: 640px) { .topnav a.link, .topnav .current { display: none; } }
.btn {
  display: inline-flex; align-items: center;
  font-family: var(--display); font-weight: 700;
  font-size: 12px; letter-spacing: 0.08em; text-transform: uppercase;
  border-radius: 6px; text-decoration: none; padding: 9px 16px;
}
.btn.primary { background: var(--accent); color: #0f1115; }
.btn.primary:hover { background: #ffea00; }
.btn.ghost {
  background: transparent; color: var(--text-primary);
  border: 1px solid var(--border);
}
.btn.ghost:hover { background: var(--bg-elevated); }

/* Sections */
section { border-bottom: 1px solid var(--border-subtle); }
.hero { padding: 64px 0; }
@media (min-width: 640px) { .hero { padding: 80px 0; } }
.kicker {
  display: inline-flex; align-items: center; gap: 8px;
  font-family: var(--display); font-weight: 700; font-size: 11px;
  letter-spacing: 0.12em; text-transform: uppercase; color: var(--accent);
  background: var(--accent-muted); padding: 6px 12px; border-radius: 999px;
}
.bighead {
  font-family: var(--display); font-weight: 900;
  font-size: 36px; line-height: 1.05; letter-spacing: -0.02em;
  margin: 24px 0 0; max-width: 700px;
}
@media (min-width: 640px) { .bighead { font-size: 48px; } }
.bighead .yellow { color: var(--accent); }
.lead {
  margin: 24px 0 0; max-width: 640px;
  color: var(--text-secondary); font-size: 16px;
}
@media (min-width: 640px) { .lead { font-size: 18px; } }

.qa-section { padding: 64px 0; }
@media (min-width: 640px) { .qa-section { padding: 80px 0; } }
.qa-list {
  display: flex; flex-direction: column; gap: 20px;
  max-width: 860px;
}
.qa {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 12px; padding: 24px;
}
@media (min-width: 640px) { .qa { padding: 28px; } }
.qa dt {
  font-family: var(--display); font-weight: 700;
  font-size: 18px; color: var(--text-primary); margin: 0;
}
@media (min-width: 640px) { .qa dt { font-size: 20px; } }
.qa dd {
  margin: 12px 0 0; color: var(--text-secondary);
  font-size: 15px; line-height: 1.6;
}
@media (min-width: 640px) { .qa dd { font-size: 16px; } }

.final {
  text-align: center; padding: 64px 0;
}
@media (min-width: 640px) { .final { padding: 80px 0; } }
.final h2 {
  font-family: var(--display); font-weight: 900;
  font-size: 28px; line-height: 1.1; letter-spacing: -0.01em;
  margin: 0 auto; max-width: 640px;
}
@media (min-width: 640px) { .final h2 { font-size: 40px; } }
.final p {
  margin: 20px auto 0; max-width: 520px;
  color: var(--text-secondary); font-size: 16px;
}
.cta-row {
  display: flex; justify-content: center; flex-wrap: wrap;
  gap: 12px; margin-top: 32px;
}
.cta-row .btn { padding: 14px 22px; font-size: 13px; }

footer {
  max-width: 1200px; margin: 0 auto; padding: 40px 20px;
}
@media (min-width: 640px) { footer { padding: 40px 32px; } }
.foot-inner {
  display: flex; flex-direction: column; align-items: flex-start;
  gap: 16px; padding-top: 32px;
  border-top: 1px solid var(--border-subtle);
  color: var(--text-tertiary); font-size: 12px;
}
@media (min-width: 640px) {
  .foot-inner { flex-direction: row; align-items: center; justify-content: space-between; }
}
.foot-left {
  display: flex; align-items: center; gap: 16px;
}
.foot-links {
  display: flex; align-items: center; gap: 20px;
}
.foot-links a {
  color: var(--text-tertiary); text-decoration: none;
}
.foot-links a:hover { color: var(--text-primary); }.logo-img { height: 48px; width: auto; display: block; }
.logo-img-sm { height: 40px; width: auto; display: block; }

/* Category tabs (CSS-only via :target) */
.tabs {
  display: flex; flex-wrap: wrap; gap: 8px;
  margin-bottom: 32px;
}
.tab {
  font-family: var(--display); font-weight: 700;
  font-size: 12px; letter-spacing: 0.06em; text-transform: uppercase;
  color: var(--text-secondary); text-decoration: none;
  padding: 8px 14px; border-radius: 999px;
  border: 1px solid var(--border);
}
.tab:hover { color: var(--text-primary); background: var(--bg-elevated); }
.panel { display: none; }
.panel:target { display: block; }
.qa-section:not(:has(.panel:target)) #start { display: block; }
.qa-section:not(:has(.panel:target)) .tab[href="#start"],
.tab[href="#start"]:focus {
  color: var(--accent); border-color: var(--accent);
  background: var(--accent-muted);
}
.tab[href="#what"]:focus,
.tab[href="#ai"]:focus,
.tab[href="#privacy"]:focus {
  color: var(--accent); border-color: var(--accent);
  background: var(--accent-muted);
}
.qa-section:has(#what:target) .tab[href="#what"],
.qa-section:has(#ai:target) .tab[href="#ai"],
.qa-section:has(#privacy:target) .tab[href="#privacy"] {
  color: var(--accent); border-color: var(--accent);
  background: var(--accent-muted);
}