/* Base reset + landing styles.
   Locked from FRONTEND_SPEC.md §1 (type + buttons) and §2 (landing sections). */

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg-page);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
button { font-family: inherit; }

/* ─── buttons ────────────────────────────────────────────────────── */
.btn-primary {
  background: var(--cta-bg);
  color: var(--gold);
  font-family: inherit;            /* buttons get a UA font by default — force the site stack */
  font-weight: 700;
  font-size: 16px;
  letter-spacing: .3px;
  border: 0;
  border-radius: 6px;              /* Button-42 corners */
  height: 44px;                    /* fixed shape — 40px Button-42 + a touch for the 15% intent */
  line-height: 44px;
  padding: 0 24px;
  display: inline-block;
  vertical-align: top;
  text-align: center;              /* center text when the element is given an explicit width */
  text-decoration: none;           /* anchors styled as buttons need this explicit */
  cursor: pointer;
  outline: 0;
  box-shadow: var(--cta-rest-shadow);
  transition: box-shadow .2s ease;
  -webkit-user-select: none;
  user-select: none;
}
.btn-primary:hover  { box-shadow: var(--cta-glow); }
.btn-primary:disabled {
  opacity: .55;
  cursor: not-allowed;
  box-shadow: none;
}
.btn-primary.compact {
  height: 36px;
  line-height: 36px;
  padding: 0 18px;
  font-size: 14px;
}

.btn-ghost {
  background: transparent;
  color: var(--gold);
  font-family: inherit;
  font-weight: 600;
  border: 1px solid var(--border-dashed);
  border-radius: var(--radius-button);
  padding: 11px 21px;
  font-size: 14px;
  display: inline-block;
  vertical-align: top;
  text-align: center;
  text-decoration: none;
  cursor: pointer;
  transition: border-color .15s ease;
}
.btn-ghost:hover { border-color: var(--gold); }

.nav-link {
  color: var(--text-secondary);
  font-size: 13.5px;
  font-weight: 500;
  cursor: pointer;
  letter-spacing: .2px;
  transition: color .15s ease;
}
.nav-link:hover { color: var(--text-primary); }
.nav-link.is-cta { color: var(--gold); }

/* ─── layout shell ───────────────────────────────────────────────── */
nav.site-nav {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 34px;
  background: rgba(26, 17, 36, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 0.5px solid var(--bg-inset);
}
.brand {
  display: flex;
  align-items: baseline;
  gap: 7px;
}
.brand .mark {
  font-size: 17px;
  font-weight: 700;
  color: var(--gold);
  letter-spacing: .5px;
}
.brand .suffix {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
  letter-spacing: 2px;
  text-transform: uppercase;
}
.nav-center {
  display: flex;
  align-items: center;
  gap: 26px;
}
.nav-right {
  display: flex;
  align-items: center;
  gap: 14px;
}

/* ─── sections ───────────────────────────────────────────────────── */
section { border-bottom: 0.5px solid var(--bg-inset); }
section.alt { background: var(--bg-raised); }
.section-pad { padding: 48px 34px; }
.section-pad-lg { padding: 64px 34px 56px; }
.section-pad-cta { padding: 60px 34px; }

h1.hero-headline {
  font-size: 44px;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -.5px;
  line-height: 1.1;
  max-width: 560px;
  margin: 0 auto;
}
h1.hero-headline .accent { color: var(--gold); }

.section-title {
  font-size: 26px;
  font-weight: 700;
  color: var(--text-primary);
  text-align: center;
  letter-spacing: .2px;
  margin: 0 0 8px;
}
.section-subtitle {
  font-size: 14px;
  color: var(--text-secondary);
  text-align: center;
  margin: 0 auto 32px;
  max-width: 430px;
  line-height: 1.6;
}

.eyebrow {
  display: inline-block;
  font-size: 12px;
  font-weight: 600;
  color: var(--gold);
  background: var(--bg-inset);
  border-radius: var(--radius-pill);
  padding: 5px 14px;
  letter-spacing: .5px;
}

.hero-section { text-align: center; }
.hero-sub {
  font-size: 16px;
  color: var(--text-secondary);
  max-width: 440px;
  margin: 18px auto 28px;
  line-height: 1.6;
}
.hero-sub em { color: var(--gold-text-soft); font-style: normal; }
.hero-ctas { display: flex; gap: 12px; justify-content: center; }
.hero-micro {
  font-size: 12px;
  color: var(--text-faint);
  margin-top: 18px;
}

/* ─── cards ──────────────────────────────────────────────────────── */
.card {
  background: var(--bg-card);
  border: 0.5px solid var(--border);
  border-radius: var(--radius-card);
  padding: 22px;
}
.card.featured { border-color: var(--gold); }
.card-grid {
  display: flex;
  gap: 16px;
}
.card-grid .card { flex: 1; }

.detect-icon { font-size: 22px; color: var(--gold); display: block; }
.card-eyebrow {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-secondary);
  letter-spacing: .5px;
}
.card-eyebrow.is-featured { color: var(--gold); }
.card-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-primary);
  margin: 8px 0 4px;
}
.card-body {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* pillars */
.pillars { display: flex; gap: 16px; }
.pillar { flex: 1; }
.pillar-icon { font-size: 24px; color: var(--gold); }
.pillar h3 {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-primary);
  margin: 12px 0 6px;
}
.pillar p {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.55;
  margin: 0;
}

/* result preview */
.result-preview {
  max-width: 440px;
  margin: 0 auto;
}
.result-head {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin-bottom: 12px;
}
.result-head .pai {
  font-size: 30px;
  font-weight: 700;
  color: var(--gold);
  line-height: 1;
}
.result-head .sigma {
  font-size: 13px;
  color: var(--text-secondary);
}
.result-head .verdict {
  margin-left: auto;
  font-size: 13px;
  font-weight: 700;
  color: var(--verdict-ai);
}

.bar {
  height: 5px;
  border-radius: 4px;
  background: var(--bg-inset);
  overflow: hidden;
  margin-bottom: 5px;
}
.bar > i {
  display: block;
  height: 100%;
  background: var(--gold);
  border-radius: 4px;
}

.head-row {
  display: flex;
  justify-content: space-between;
  font-size: 12px;
  color: var(--text-primary);
  margin-bottom: 4px;
}
.head-row .score {
  color: var(--gold);
  font-weight: 700;
}

/* pricing */
.pricing-reminder {
  font-size: 14px;
  color: var(--text-secondary);
  text-align: center;
  margin: 0 auto 28px;
}
.pricing-grid {
  display: flex;
  gap: 14px;
  align-items: stretch;
}
.pricing-grid .card {
  display: flex;
  flex-direction: column;
}
.pricing-amount {
  font-size: 24px;
  font-weight: 700;
  color: var(--text-primary);
  margin: 6px 0;
}
.pricing-unit {
  font-size: 12.5px;
  color: var(--text-secondary);
  margin-bottom: 16px;
}
.pricing-cta {
  margin-top: auto;
  width: 100%;
}

/* developers */
.dev-section {
  padding: 48px 34px;
  display: flex;
  gap: 32px;
  align-items: center;
  border-bottom: 0.5px solid var(--bg-inset);
}
.dev-copy { flex: 1; }
.dev-copy h2 {
  font-size: 24px;
  font-weight: 700;
  color: var(--text-primary);
  margin: 0 0 8px;
}
.dev-copy p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.6;
  margin: 0 0 18px;
}
.code-block {
  flex: 1;
  background: var(--bg-code);
  border: 0.5px solid var(--border);
  border-radius: 10px;
  padding: 18px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--text-secondary);
}
.code-block .method { color: var(--gold); }
.code-block .label  { color: var(--text-faint); }
.code-block .real   { color: var(--verdict-real); }
.code-block .ai     { color: var(--verdict-ai); }

/* FAQ */
.faq-list { max-width: 560px; margin: 0 auto; }
.faq-item {
  border-bottom: 0.5px solid var(--bg-inset);
}
.faq-item > summary {
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 0;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-primary);
  cursor: pointer;
}
.faq-item > summary::-webkit-details-marker { display: none; }
.faq-item .caret {
  color: var(--gold);
  transition: transform .15s ease;
  font-size: 18px;
  line-height: 1;
}
.faq-item[open] .caret { transform: rotate(180deg); }
.faq-item .answer {
  padding: 0 0 16px;
  font-size: 13.5px;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* final CTA */
.cta-band {
  text-align: center;
  background: var(--bg-raised);
}
.cta-band .line {
  font-size: 30px;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -.3px;
}
.cta-band .btn-primary { margin-top: 24px; }

/* footer */
footer.site-foot {
  padding: 36px 34px;
  display: flex;
  justify-content: space-between;
  gap: 32px;
}
.foot-brand .meta {
  font-size: 12px;
  color: var(--text-faint);
  max-width: 220px;
  line-height: 1.5;
  margin-top: 10px;
}
.foot-cols {
  display: flex;
  gap: 48px;
}
.foot-col h4 {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: .5px;
  text-transform: uppercase;
  margin: 0 0 8px;
}
.foot-col a {
  display: block;
  color: var(--text-faint);
  font-size: 13px;
  margin-top: 9px;
  transition: color .15s ease;
  cursor: pointer;
}
.foot-col a:hover { color: var(--gold); }

/* sr-only for accessibility */
.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* responsive — single breakpoint, narrow phones */
@media (max-width: 720px) {
  nav.site-nav { padding: 12px 18px; }
  .nav-center { display: none; }
  .section-pad, .dev-section { padding: 36px 18px; }
  .section-pad-lg { padding: 48px 18px 40px; }
  h1.hero-headline { font-size: 34px; }
  .card-grid, .pillars, .pricing-grid, .dev-section { flex-direction: column; }
  footer.site-foot { flex-direction: column; gap: 28px; }
  .foot-cols { gap: 28px; flex-wrap: wrap; }
}