/* ============================================
   KOS Design System v2.0
   Custom properties + utility overrides
   Used alongside Tailwind CDN
   ============================================ */

/* --- Design Tokens --- */
:root {
  /* Brand Colors */
  --kos-blue-900: #002B4D;
  --kos-blue-700: #005395;
  --kos-blue-500: #0077CC;
  --kos-blue-400: #2E9BDB;
  --kos-blue-100: #E8F4FD;
  --kos-blue-50:  #F0F7FF;

  --kos-accent:      #E63946;
  --kos-accent-dark: #C1121F;
  --kos-accent-light:#FEE2E2;

  --kos-green:  #059669;
  --kos-green-light: #D1FAE5;
  --kos-amber:  #D97706;
  --kos-amber-light: #FEF3C7;

  /* Neutrals */
  --kos-gray-900: #111827;
  --kos-gray-700: #374151;
  --kos-gray-500: #6B7280;
  --kos-gray-400: #9CA3AF;
  --kos-gray-300: #D1D5DB;
  --kos-gray-200: #E5E7EB;
  --kos-gray-100: #F3F4F6;
  --kos-gray-50:  #F9FAFB;
  --kos-white:    #FFFFFF;

  /* Typography */
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-display: 'Inter', system-ui, -apple-system, sans-serif;

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* --- Base Reset & Defaults --- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  color: var(--kos-gray-700);
  background-color: var(--kos-white);
  line-height: 1.6;
}

/* --- Focus Styles (Accessibility) --- */
:focus-visible {
  outline: 2px solid var(--kos-blue-500);
  outline-offset: 2px;
  border-radius: 4px;
}

/* --- Skip Link --- */
.skip-link {
  position: absolute;
  top: -100%;
  left: 50%;
  transform: translateX(-50%);
  background: var(--kos-blue-700);
  color: white;
  padding: 0.75rem 1.5rem;
  border-radius: 0 0 0.5rem 0.5rem;
  z-index: 9999;
  font-weight: 600;
  transition: top var(--transition-fast);
}
.skip-link:focus {
  top: 0;
}

/* --- Button System --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-weight: 600;
  border-radius: 0.5rem;
  transition: all var(--transition-base);
  cursor: pointer;
  border: 2px solid transparent;
  text-decoration: none;
  line-height: 1;
  white-space: nowrap;
}
.btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1);
}
.btn:active {
  transform: translateY(0);
}

.btn-sm {
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
}
.btn-md {
  padding: 0.75rem 1.5rem;
  font-size: 0.9375rem;
}
.btn-lg {
  padding: 0.875rem 2rem;
  font-size: 1rem;
}
.btn-xl {
  padding: 1rem 2.5rem;
  font-size: 1.125rem;
}

.btn-primary {
  background: var(--kos-blue-700);
  color: white;
}
.btn-primary:hover {
  background: var(--kos-blue-500);
  color: white;
}

.btn-accent {
  background: var(--kos-accent);
  color: white;
}
.btn-accent:hover {
  background: var(--kos-accent-dark);
  color: white;
}

.btn-outline {
  background: transparent;
  border-color: var(--kos-blue-700);
  color: var(--kos-blue-700);
}
.btn-outline:hover {
  background: var(--kos-blue-700);
  color: white;
}

.btn-white {
  background: white;
  color: var(--kos-blue-700);
}
.btn-white:hover {
  background: var(--kos-gray-100);
  color: var(--kos-blue-700);
}

.btn-ghost {
  background: transparent;
  color: var(--kos-blue-700);
  border-color: transparent;
}
.btn-ghost:hover {
  background: var(--kos-blue-50);
  box-shadow: none;
  transform: none;
}

/* --- Form System --- */
.form-group {
  margin-bottom: 1.25rem;
}
.form-label {
  display: block;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--kos-gray-700);
  margin-bottom: 0.375rem;
}
.form-input,
.form-select,
.form-textarea {
  width: 100%;
  padding: 0.625rem 0.875rem;
  font-size: 1rem;
  line-height: 1.5;
  color: var(--kos-gray-900);
  background: var(--kos-white);
  border: 1.5px solid var(--kos-gray-300);
  border-radius: 0.5rem;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  font-family: inherit;
}
.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  border-color: var(--kos-blue-500);
  box-shadow: 0 0 0 3px rgba(0,119,204,0.15);
  outline: none;
}
.form-input::placeholder {
  color: var(--kos-gray-400);
}
.form-input.error {
  border-color: var(--kos-accent);
}
.form-hint {
  font-size: 0.8125rem;
  color: var(--kos-gray-500);
  margin-top: 0.25rem;
}
.form-error {
  font-size: 0.8125rem;
  color: var(--kos-accent);
  margin-top: 0.25rem;
}

/* --- Card System --- */
.card {
  background: var(--kos-white);
  border-radius: 0.75rem;
  border: 1px solid var(--kos-gray-200);
  overflow: hidden;
  transition: all var(--transition-base);
}
.card:hover {
  box-shadow: 0 10px 15px -3px rgba(0,0,0,0.08);
  border-color: var(--kos-gray-300);
}
.card-featured {
  border-color: var(--kos-blue-500);
  box-shadow: 0 4px 6px -1px rgba(0,119,204,0.1);
  position: relative;
}
.card-featured::before {
  content: 'Most Popular';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  background: var(--kos-blue-700);
  color: white;
  text-align: center;
  padding: 0.375rem;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* --- Badge System --- */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.25rem 0.625rem;
  font-size: 0.75rem;
  font-weight: 600;
  border-radius: 9999px;
  line-height: 1;
}
.badge-blue {
  background: var(--kos-blue-100);
  color: var(--kos-blue-700);
}
.badge-green {
  background: var(--kos-green-light);
  color: var(--kos-green);
}
.badge-amber {
  background: var(--kos-amber-light);
  color: var(--kos-amber);
}
.badge-red {
  background: var(--kos-accent-light);
  color: var(--kos-accent);
}

/* --- Section Styling --- */
.section {
  padding: 4rem 0;
}
.section-lg {
  padding: 5rem 0;
}
.section-sm {
  padding: 2.5rem 0;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--kos-gray-900);
  line-height: 1.2;
  letter-spacing: -0.025em;
}
.section-subtitle {
  font-size: 1.125rem;
  color: var(--kos-gray-500);
  max-width: 40rem;
  line-height: 1.6;
}

/* --- Trust Bar --- */
.trust-bar {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 2rem;
  flex-wrap: wrap;
}
.trust-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--kos-gray-500);
  font-size: 0.875rem;
}
.trust-item svg {
  color: var(--kos-green);
  flex-shrink: 0;
}

/* --- Pricing Table --- */
.pricing-card {
  display: flex;
  flex-direction: column;
  height: 100%;
}
.pricing-header {
  padding: 1.5rem;
  text-align: center;
}
.pricing-price {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--kos-gray-900);
  line-height: 1;
}
.pricing-price .period {
  font-size: 1rem;
  font-weight: 400;
  color: var(--kos-gray-500);
}
.pricing-features {
  padding: 0 1.5rem 1.5rem;
  flex: 1;
}
.pricing-features li {
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  padding: 0.5rem 0;
  font-size: 0.9375rem;
  color: var(--kos-gray-700);
}
.pricing-features li svg {
  color: var(--kos-green);
  flex-shrink: 0;
  margin-top: 0.125rem;
}
.pricing-footer {
  padding: 1.5rem;
  border-top: 1px solid var(--kos-gray-200);
}

/* --- Mobile Navigation --- */
.mobile-nav-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  z-index: 40;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-slow);
}
.mobile-nav-overlay.active {
  opacity: 1;
  visibility: visible;
}

.mobile-nav {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: 320px;
  max-width: 85vw;
  background: white;
  z-index: 50;
  transform: translateX(100%);
  transition: transform var(--transition-slow);
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}
.mobile-nav.active {
  transform: translateX(0);
}

.mobile-nav-sub {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-slow);
}
.mobile-nav-sub.open {
  max-height: 600px;
}
.mobile-nav-toggle-sub[aria-expanded="true"] svg {
  transform: rotate(180deg);
}

/* --- Sticky Header --- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  background: white;
  transition: box-shadow var(--transition-base);
}
.site-header.scrolled {
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

/* --- Hero Section --- */
.hero {
  background: linear-gradient(135deg, var(--kos-blue-900) 0%, var(--kos-blue-700) 100%);
  color: white;
  position: relative;
  overflow: hidden;
}
.hero::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 4rem;
  background: linear-gradient(to top, white, transparent);
  pointer-events: none;
}
.hero-pattern {
  position: absolute;
  inset: 0;
  opacity: 0.05;
  background-image: radial-gradient(circle at 25% 25%, white 1px, transparent 1px);
  background-size: 40px 40px;
}

/* --- Testimonial --- */
.testimonial-card {
  position: relative;
  padding: 1.5rem;
}
.testimonial-card::before {
  content: '\201C';
  position: absolute;
  top: 0.5rem;
  left: 1rem;
  font-size: 4rem;
  line-height: 1;
  color: var(--kos-blue-100);
  font-family: Georgia, serif;
}

/* --- Availability Checker --- */
.availability-widget {
  background: var(--kos-blue-50);
  border: 2px solid var(--kos-blue-100);
  border-radius: 1rem;
  padding: 2rem;
}
.availability-input-group {
  display: flex;
  gap: 0.75rem;
  max-width: 28rem;
}
.availability-input-group .form-input {
  flex: 1;
  font-size: 1.125rem;
  padding: 0.75rem 1rem;
}

/* --- FAQ Accordion --- */
details.faq-item {
  border: 1px solid var(--kos-gray-200);
  border-radius: 0.75rem;
  transition: all var(--transition-base);
}
details.faq-item + details.faq-item {
  margin-top: 0.5rem;
}
details.faq-item[open] {
  border-color: var(--kos-blue-100);
  background: var(--kos-blue-50);
}
details.faq-item summary {
  padding: 1rem 1.25rem;
  font-weight: 600;
  color: var(--kos-gray-900);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
details.faq-item summary::-webkit-details-marker {
  display: none;
}
details.faq-item summary::after {
  content: '+';
  font-size: 1.25rem;
  font-weight: 400;
  color: var(--kos-gray-400);
  transition: transform var(--transition-base);
  flex-shrink: 0;
}
details.faq-item[open] summary::after {
  content: '−';
  color: var(--kos-blue-500);
}
details.faq-item .faq-answer {
  padding: 0 1.25rem 1rem;
  font-size: 0.9375rem;
  color: var(--kos-gray-600);
  line-height: 1.7;
}

/* --- Quiz Card --- */
.quiz-option {
  border: 2px solid var(--kos-gray-200);
  border-radius: 0.75rem;
  padding: 1rem;
  cursor: pointer;
  transition: all var(--transition-base);
  text-align: center;
  font-weight: 600;
}
.quiz-option:hover {
  border-color: var(--kos-gray-300);
  background: var(--kos-gray-50);
}

/* --- Stats Counter --- */
.stat-number {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--kos-blue-700);
  line-height: 1;
}
.stat-label {
  font-size: 0.875rem;
  color: var(--kos-gray-500);
  margin-top: 0.25rem;
}

/* --- Animations --- */
@media (prefers-reduced-motion: no-preference) {
  .fade-in-up {
    opacity: 0;
    transform: translateY(1.5rem);
    transition: opacity 0.5s ease, transform 0.5s ease;
  }
  .fade-in-up.visible {
    opacity: 1;
    transform: translateY(0);
  }
}
@media (prefers-reduced-motion: reduce) {
  .fade-in-up {
    opacity: 1;
    transform: none;
  }
}

/* --- Responsive Utilities --- */
@media (max-width: 640px) {
  .section { padding: 2.5rem 0; }
  .section-lg { padding: 3rem 0; }
  .section-title { font-size: 1.75rem; }
  .pricing-price { font-size: 2rem; }
  .hero { padding-top: 2rem; padding-bottom: 3rem; }
}

@media (max-width: 1024px) {
  .desktop-only { display: none !important; }
}
@media (min-width: 1025px) {
  .mobile-only { display: none !important; }
}

/* --- Quick Action Cards --- */
.quick-action {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 1.5rem;
  border-radius: 0.75rem;
  border: 1px solid var(--kos-gray-200);
  background: var(--kos-white);
  transition: all var(--transition-base);
  text-decoration: none;
  color: inherit;
}
.quick-action:hover {
  border-color: var(--kos-blue-500);
  box-shadow: 0 4px 12px rgba(0,119,204,0.1);
  transform: translateY(-2px);
}
.quick-action-icon {
  width: 3rem;
  height: 3rem;
  border-radius: 0.75rem;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 0.75rem;
}
.quick-action-title {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--kos-gray-900);
}
.quick-action-desc {
  font-size: 0.8125rem;
  color: var(--kos-gray-500);
  margin-top: 0.25rem;
}

/* --- Prose (for CMS content) --- */
.prose h2 { font-size: 1.5rem; font-weight: 700; color: var(--kos-gray-900); margin: 2rem 0 0.75rem; }
.prose h3 { font-size: 1.25rem; font-weight: 600; color: var(--kos-gray-900); margin: 1.5rem 0 0.5rem; }
.prose p { margin-bottom: 1rem; line-height: 1.7; }
.prose ul, .prose ol { margin: 1rem 0; padding-left: 1.5rem; }
.prose li { margin-bottom: 0.5rem; }
.prose a { color: var(--kos-blue-500); text-decoration: underline; }
.prose a:hover { color: var(--kos-blue-700); }

/* --- Print --- */
@media print {
  .site-header, .site-footer, .mobile-nav, .mobile-nav-overlay { display: none; }
  .hero { background: white; color: black; }
  .btn { border: 1px solid #333; }
}