/* Zapon Shared — calculator page base layer */
:root {
  --z-primary: #6366f1;
  --z-primary-dark: #4f46e5;
  --z-secondary: #8b5cf6;
  --z-accent: #fbbf24;
  --z-dark: #0f172a;
  --z-gray: #64748b;
  --z-gray-light: #94a3b8;
  --z-light: #f8fafc;
  --z-white: #ffffff;
  --z-border: #e2e8f0;
  --z-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #a855f7 100%);
  --z-radius: 12px;
  --z-shadow: 0 4px 6px -1px rgba(0,0,0,0.1);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--z-light);
  color: var(--z-dark);
  line-height: 1.6;
  min-height: 100vh;
}

/* Navbar */
.z-navbar {
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--z-border);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.z-nav-container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0.875rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.z-logo {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  text-decoration: none;
}

.z-logo-mark {
  width: 40px;
  height: 40px;
  flex-shrink: 0;
}

.z-logo-text {
  font-size: 1.5rem;
  font-weight: 800;
  background: var(--z-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.z-nav-links {
  display: flex;
  gap: 1.5rem;
}

.z-nav-links a {
  color: var(--z-gray);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.95rem;
  transition: color 0.2s;
}

.z-nav-links a:hover {
  color: var(--z-primary);
}

.z-mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--z-dark);
  cursor: pointer;
}

/* Footer */
.z-footer {
  background: var(--z-dark);
  color: var(--z-gray-light);
  padding: 2rem 0;
  margin-top: 4rem;
  text-align: center;
  font-size: 0.875rem;
  line-height: 1.8;
}

.z-footer a {
  color: var(--z-gray-light);
  text-decoration: none;
  transition: color 0.2s;
}

.z-footer a:hover {
  color: var(--z-white);
}

.z-footer-inner {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 2rem;
}

.z-footer-links {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  flex-wrap: wrap;
  margin-bottom: 0.75rem;
}

/* SEO content section (FAQ + cross-links) */
.z-seo-content {
  max-width: 900px;
  margin: 3rem auto 0;
  padding: 0 2rem;
}

.z-seo-inner {
  background: var(--z-white);
  border-radius: var(--z-radius);
  padding: 2rem;
  box-shadow: var(--z-shadow);
}

.z-seo-inner h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 1.25rem;
  color: var(--z-dark);
}

.z-seo-inner h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin-top: 2rem;
  margin-bottom: 0.75rem;
  color: var(--z-dark);
}

.z-seo-inner details {
  border-bottom: 1px solid var(--z-border);
  padding: 0.875rem 0;
}

.z-seo-inner details:last-of-type {
  border-bottom: none;
}

.z-seo-inner summary {
  font-weight: 600;
  cursor: pointer;
  color: var(--z-dark);
  font-size: 0.95rem;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.z-seo-inner summary::after {
  content: '+';
  font-size: 1.25rem;
  color: var(--z-primary);
  font-weight: 700;
  transition: transform 0.2s;
}

.z-seo-inner details[open] summary::after {
  content: '−';
}

.z-seo-inner details p {
  margin-top: 0.75rem;
  color: var(--z-gray);
  font-size: 0.9rem;
  line-height: 1.7;
}

.z-related-links {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.z-related-links li a {
  display: inline-block;
  padding: 0.5rem 1rem;
  background: rgba(99,102,241,0.08);
  color: var(--z-primary);
  border-radius: 50px;
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  transition: background 0.2s, color 0.2s;
}

.z-related-links li a:hover {
  background: var(--z-primary);
  color: var(--z-white);
}

/* Focus visible */
.z-nav-links a:focus-visible,
.z-mobile-menu-btn:focus-visible {
  outline: 3px solid rgba(99,102,241,0.45);
  outline-offset: 2px;
}

/* Mobile nav */
@media (max-width: 768px) {
  .z-nav-links {
    display: none;
  }
  .z-nav-links.active {
    display: flex;
    position: absolute;
    top: calc(100% + 8px);
    right: 1rem;
    flex-direction: column;
    min-width: 180px;
    background: var(--z-white);
    border: 1px solid var(--z-border);
    border-radius: var(--z-radius);
    padding: 0.75rem;
    box-shadow: 0 20px 40px rgba(0,0,0,0.15);
    gap: 0.5rem;
    z-index: 1001;
  }
  .z-mobile-menu-btn {
    display: block;
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}