/* ═══════════════════════════════════════════
   TUVO — Layout: Nav, Header, Main, Sections
   ═══════════════════════════════════════════ */

/* ── Container ── */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

/* ═══════════════════════════════════════════
   Full Navigation (home.html)
   Frosted glass, sticky, with brand + links
   ═══════════════════════════════════════════ */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(250, 250, 245, 0.85);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--color-border-accent);
  height: var(--nav-height);
  transition: box-shadow var(--duration-normal) ease;
}
.nav.scrolled {
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.06);
}
.nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav-brand {
  font-size: 22px;
  font-weight: 600;
  color: var(--color-text);
  letter-spacing: -0.02em;
  transition: opacity var(--duration-fast) ease;
}
.nav-brand:hover { opacity: 0.7; color: var(--color-text); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 36px;
}
.nav-links a {
  font-size: 14px;
  font-weight: 500;
  color: var(--color-text-secondary);
  position: relative;
  padding: 4px 0;
}
.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-primary);
  border-radius: 1px;
  transition: width var(--duration-normal) var(--ease-smooth);
}
.nav-links a:hover { color: var(--color-text); }
.nav-links a:hover::after { width: 100%; }

.nav-cta { display: flex; align-items: center; }
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-xs);
  color: var(--color-text);
  transition: opacity var(--duration-fast) ease;
}
.nav-toggle:hover { opacity: 0.6; }

/* ═══════════════════════════════════════════
   Subpage Header (fixed 56px, back button)
   Used by all pages/*.html
   ═══════════════════════════════════════════ */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: rgba(250, 250, 245, 0.9);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  border-bottom: 1px solid var(--color-border);
}

.back-btn {
  position: absolute;
  left: 1rem;
  background: none;
  border: none;
  color: var(--color-text-muted);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0.5rem;
  transition: color 0.3s;
}
.back-btn:hover { color: var(--color-text); }

.header-title {
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}

/* ── Subpage main content area ── */
.main {
  padding: 70px var(--space-sm) var(--space-xl);
  max-width: 500px;
  margin: 0 auto;
}

/* ═══════════════════════════════════════════
   Sections — alternating with generous spacing
   ═══════════════════════════════════════════ */
section {
  padding: var(--space-3xl) 0;
  position: relative;
}
.section-bg-cream { background: var(--color-bg); }
.section-bg-white { background: var(--color-bg-alt); }
.section-bg-warm { background: var(--color-bg-warm); }

.section-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: var(--space-sm);
}
.section-label::before {
  content: '';
  width: 24px;
  height: 2px;
  background: var(--color-primary);
  border-radius: 1px;
}

.section-title {
  font-size: clamp(28px, 4.5vw, 44px);
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: -0.02em;
  color: var(--color-text);
  margin-bottom: var(--space-sm);
}

.section-subtitle {
  font-size: clamp(16px, 2vw, 19px);
  color: var(--color-text-secondary);
  max-width: 560px;
  line-height: 1.7;
}

.section-header-center {
  text-align: center;
  margin-bottom: var(--space-2xl);
}
.section-header-center .section-subtitle {
  margin-left: auto;
  margin-right: auto;
}
.section-header-center .section-label::before { display: none; }

/* ── Version Footer (subpages) ── */
.version-footer {
  text-align: center;
  padding: var(--space-lg) 0;
  color: var(--color-text-muted);
  font-size: 0.75rem;
}

/* ═══════════════════════════════════════════
   Mobile — 768px breakpoint (layout)
   ═══════════════════════════════════════════ */
@media (max-width: 768px) {
  :root {
    --space-3xl: 4rem;
    --space-2xl: 3rem;
  }

  section { padding: var(--space-2xl) 0; }
  .container { padding: 0 var(--space-md); }

  .nav-links { display: none; }
  .nav-toggle { display: block; }
  .nav-links.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: rgba(250, 250, 245, 0.98);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    padding: var(--space-lg);
    gap: var(--space-md);
    border-bottom: 1px solid var(--color-border);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.08);
  }
  .nav-links.open a::after { display: none; }
  .nav-cta { display: none; }
  .nav-links.open .mobile-cta { display: inline-flex; }
}