/* ===== CSS VARIABLES & THEME ===== */
:root {
  /* Colors - Light Theme */
  --color-primary: #4361ee;
  --color-primary-dark: #3a56d4;
  --color-secondary: #7209b7;
  --color-accent: #4cc9f0;

  --color-bg: #ffffff;
  --color-bg-alt: #f8f9fa;
  --color-bg-card: #ffffff;
  --color-text: #1e293b;
  --color-text-light: #64748b;
  --color-text-inverse: #ffffff;

  --color-border: #e2e8f0;
  --color-shadow: rgba(0, 0, 0, 0.08);
  --color-shadow-hover: rgba(0, 0, 0, 0.12);

  /* Gradients */
  --gradient-primary: linear-gradient(135deg, #4361ee, #7209b7);
  --gradient-hero: linear-gradient(135deg, rgba(67, 97, 238, 0.7), rgba(114, 9, 183, 0.65));

  /* Typography */
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-heading: 'Playfair Display', serif;

  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  --text-5xl: 3rem;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;

  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;

  /* Transitions & Animations */
  --transition-fast: 150ms ease;
  --transition-normal: 300ms ease;
  --transition-slow: 500ms ease;

  --shadow-sm: 0 1px 2px 0 var(--color-shadow);
  --shadow-md: 0 4px 6px -1px var(--color-shadow), 0 2px 4px -1px var(--color-shadow);
  --shadow-lg: 0 10px 15px -3px var(--color-shadow), 0 4px 6px -2px var(--color-shadow);
  --shadow-xl: 0 20px 25px -5px var(--color-shadow), 0 10px 10px -5px var(--color-shadow);

  /* Z-index */
  --z-dropdown: 100;
  --z-sticky: 200;
  --z-modal: 300;
  --z-toast: 400;
}

/* Dark Theme */
[data-theme="dark"] {
  --color-bg: #0f172a;
  --color-bg-alt: #1e293b;
  --color-bg-card: #1e293b;
  --color-text: #f1f5f9;
  --color-text-light: #94a3b8;
  --color-border: #334155;
  --color-shadow: rgba(0, 0, 0, 0.3);
  --color-shadow-hover: rgba(0, 0, 0, 0.4);
}

/* ===== RESET & BASE ===== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-body);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  overflow-x: hidden;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary-dark);
}

ul {
  list-style: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

input, textarea, select {
  font-family: inherit;
  font-size: inherit;
}

/* ===== UTILITIES ===== */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-primary);
  color: white;
  padding: var(--space-sm) var(--space-md);
  z-index: var(--z-modal);
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: 0;
}

.section {
  padding: var(--space-3xl) 0;
}

.section-alt {
  background-color: var(--color-bg-alt);
}

.section-header {
  text-align: center;
  max-width: 600px;
  margin: 0 auto var(--space-2xl);
}

.section-title {
  font-family: var(--font-heading);
  font-size: var(--text-3xl);
  font-weight: 700;
  margin-bottom: var(--space-sm);
  color: var(--color-text);
}

.section-subtitle {
  font-size: var(--text-lg);
  color: var(--color-text-light);
}

/* ===== BUTTONS ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-lg);
  border-radius: var(--radius-md);
  font-weight: 500;
  font-size: var(--text-sm);
  transition: all var(--transition-fast);
  cursor: pointer;
}

.btn-primary {
  background: var(--gradient-primary);
  color: var(--color-text-inverse);
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
  color: var(--color-text-inverse);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn-outline:hover {
  background: var(--color-primary);
  color: white;
}

.btn-block {
  width: 100%;
}

/* ===== HEADER & NAVIGATION ===== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--z-sticky);
  padding: var(--space-md) 0;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
  transition: all var(--transition-normal);
}

[data-theme="dark"] .header {
  background: rgba(15, 23, 42, 0.95);
}

.header.scrolled {
  padding: var(--space-sm) 0;
  box-shadow: var(--shadow-md);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-text);
}

.nav-logo i {
  color: var(--color-primary);
  font-size: var(--text-2xl);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.nav-link {
  font-weight: 500;
  color: var(--color-text);
  position: relative;
  padding: var(--space-sm) 0;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--gradient-primary);
  transition: width var(--transition-fast);
}

.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-primary);
}

.nav-cta .btn {
  padding: var(--space-sm) var(--space-lg);
}

.nav-toggle {
  display: none;
  font-size: var(--text-2xl);
  color: var(--color-text);
  padding: var(--space-sm);
}

.theme-toggle {
  font-size: var(--text-lg);
  color: var(--color-text);
  padding: var(--space-sm);
  border-radius: var(--radius-full);
  transition: background var(--transition-fast);
  width: 40px;
  height: 40px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.theme-toggle:hover {
  background: var(--color-bg-alt);
}

/* ===== HERO SECTION ===== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: 80px;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -2;
}

.hero-bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--gradient-hero);
  z-index: -1;
}

.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  color: var(--color-text-inverse);
  padding: var(--space-3xl) 0;
}

.hero-title {
  font-family: var(--font-heading);
  font-size: clamp(var(--text-3xl), 5vw, var(--text-5xl));
  font-weight: 700;
  margin-bottom: var(--space-md);
  line-height: 1.2;
  text-shadow: 0 2px 16px rgba(0, 0, 0, 0.25);
}

.hero-title .highlight {
  background: linear-gradient(135deg, #fff, #e2e8f0);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: var(--text-lg);
  max-width: 600px;
  margin: 0 auto var(--space-2xl);
  opacity: 0.95;
  text-shadow: 0 1px 8px rgba(0, 0, 0, 0.25);
}

.search-box {
  max-width: 600px;
  margin: 0 auto var(--space-2xl);
}

.search-form {
  display: flex;
  gap: var(--space-sm);
  background: var(--color-bg);
  padding: var(--space-sm);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
}

.search-input-group {
  flex: 1;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 0 var(--space-md);
  background: var(--color-bg-alt);
  border-radius: var(--radius-md);
}

.search-input-group i {
  color: var(--color-text-light);
}

.search-input-group input {
  flex: 1;
  border: none;
  background: transparent;
  padding: var(--space-md) 0;
  color: var(--color-text);
  outline: none;
}

.search-input-group input::placeholder {
  color: var(--color-text-light);
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: var(--space-2xl);
  flex-wrap: wrap;
}

.stat {
  text-align: center;
}

.stat-number {
  display: block;
  font-size: var(--text-2xl);
  font-weight: 700;
  color: var(--color-text-inverse);
}

.stat-label {
  font-size: var(--text-sm);
  opacity: 0.9;
}

.scroll-down {
  position: absolute;
  bottom: var(--space-lg);
  left: 50%;
  transform: translateX(-50%);
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  background: rgba(255, 255, 255, 0.2);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  animation: bounce 2s infinite;
  transition: background var(--transition-fast);
}

.scroll-down:hover {
  background: rgba(255, 255, 255, 0.3);
}

@keyframes bounce {
  0%, 20%, 50%, 80%, 100% { transform: translateX(-50%) translateY(0); }
  40% { transform: translateX(-50%) translateY(-10px); }
  60% { transform: translateX(-50%) translateY(-5px); }
}

/* ===== DESTINATIONS GRID ===== */
.destinations-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-xl);
  margin-bottom: var(--space-2xl);
}

.destination-card {
  background: var(--color-bg-card);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
  display: flex;
  flex-direction: column;
}

.destination-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-xl);
}

.card-image {
  position: relative;
  height: 200px;
  overflow: hidden;
}

.card-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-slow);
}

.destination-card:hover .card-image img {
  transform: scale(1.05);
}

.card-badge {
  position: absolute;
  top: var(--space-md);
  right: var(--space-md);
  background: var(--color-primary);
  color: white;
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: 500;
}

.card-content {
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  flex: 1;
}

.card-location {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  color: var(--color-text-light);
  font-size: var(--text-sm);
  margin-bottom: var(--space-sm);
}

.card-title {
  font-size: var(--text-xl);
  font-weight: 600;
  margin-bottom: var(--space-sm);
  color: var(--color-text);
}

.card-desc {
  color: var(--color-text-light);
  margin-bottom: var(--space-lg);
  font-size: var(--text-sm);
  flex: 1;
}

.card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-md);
}

.card-price {
  font-weight: 600;
  color: var(--color-primary);
  font-size: var(--text-lg);
}

.section-cta {
  text-align: center;
}

/* ===== PACKAGES SECTION ===== */
.filters {
  display: flex;
  justify-content: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-2xl);
  flex-wrap: wrap;
}

.filter-btn {
  padding: var(--space-sm) var(--space-lg);
  border-radius: var(--radius-full);
  font-weight: 500;
  font-size: var(--text-sm);
  background: var(--color-bg-alt);
  color: var(--color-text);
  border: 2px solid transparent;
  transition: all var(--transition-fast);
}

.filter-btn:hover,
.filter-btn.active {
  background: var(--color-primary);
  color: white;
  border-color: var(--color-primary);
}

.packages-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-xl);
}

.package-card {
  background: var(--color-bg-card);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-normal), box-shadow var(--transition-normal), opacity var(--transition-normal);
  display: flex;
  flex-direction: column;
}

.package-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-xl);
}

.package-image {
  position: relative;
  height: 200px;
  overflow: hidden;
}

.package-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-slow);
}

.package-card:hover .package-image img {
  transform: scale(1.05);
}

.package-duration {
  position: absolute;
  bottom: var(--space-md);
  left: var(--space-md);
  background: rgba(255, 255, 255, 0.95);
  color: var(--color-text);
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--radius-md);
  font-size: var(--text-xs);
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.package-content {
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  flex: 1;
}

.package-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: var(--space-md);
  margin-bottom: var(--space-md);
}

.package-title {
  font-size: var(--text-xl);
  font-weight: 600;
  color: var(--color-text);
}

.package-price {
  font-size: var(--text-2xl);
  font-weight: 700;
  color: var(--color-primary);
  white-space: nowrap;
}

.package-highlights {
  margin-bottom: var(--space-lg);
  flex: 1;
}

.package-highlights li {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-sm);
  font-size: var(--text-sm);
  color: var(--color-text-light);
}

.package-highlights i {
  color: var(--color-accent);
  font-size: var(--text-xs);
}

.package-btn {
  width: 100%;
}

/* ===== TESTIMONIALS ===== */
.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-xl);
}

.testimonial-card {
  background: var(--color-bg-card);
  padding: var(--space-xl);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  border-left: 4px solid var(--color-primary);
}

.testimonial-rating {
  color: #fbbf24;
  margin-bottom: var(--space-md);
  font-size: var(--text-sm);
}

.testimonial-text {
  font-style: italic;
  margin-bottom: var(--space-lg);
  line-height: 1.7;
  color: var(--color-text);
}

.testimonial-author {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.testimonial-author img {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-full);
  object-fit: cover;
}

.testimonial-author strong {
  display: block;
  color: var(--color-text);
}

.testimonial-author span {
  font-size: var(--text-sm);
  color: var(--color-text-light);
}

/* ===== ABOUT SECTION ===== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-2xl);
  align-items: center;
}

.about-content .section-title {
  text-align: left;
  margin-bottom: var(--space-lg);
}

.about-text {
  margin-bottom: var(--space-xl);
  color: var(--color-text-light);
}

.about-features {
  display: grid;
  gap: var(--space-lg);
  margin-bottom: var(--space-xl);
}

.about-feature {
  display: flex;
  gap: var(--space-md);
}

.about-feature i {
  font-size: var(--text-2xl);
  color: var(--color-primary);
  min-width: 24px;
}

.about-feature h4 {
  font-weight: 600;
  margin-bottom: var(--space-xs);
  color: var(--color-text);
}

.about-feature p {
  font-size: var(--text-sm);
  color: var(--color-text-light);
}

.about-image {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-xl);
  min-height: 300px;
}

.about-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.about-image-overlay {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  background: linear-gradient(transparent, rgba(0,0,0,0.7));
  padding: var(--space-lg);
  color: white;
}

.about-stat {
  display: block;
  font-size: var(--text-3xl);
  font-weight: 700;
}

.about-stat-label {
  font-size: var(--text-sm);
  opacity: 0.9;
}

/* ===== CONTACT SECTION ===== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-2xl);
}

.contact-info .section-title {
  text-align: left;
}

.contact-subtitle {
  margin-bottom: var(--space-xl);
  color: var(--color-text-light);
}

.contact-details {
  margin-bottom: var(--space-xl);
}

.contact-item {
  display: flex;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
  align-items: flex-start;
}

.contact-item i {
  font-size: var(--text-xl);
  color: var(--color-primary);
  min-width: 24px;
  margin-top: 4px;
}

.contact-item strong {
  display: block;
  margin-bottom: var(--space-xs);
  color: var(--color-text);
}

.contact-item a,
.contact-item span {
  color: var(--color-text-light);
}

.contact-item a:hover {
  color: var(--color-primary);
}

.social-links {
  display: flex;
  gap: var(--space-md);
}

.social-links a {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  background: var(--color-bg-alt);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text);
  transition: all var(--transition-fast);
}

.social-links a:hover {
  background: var(--color-primary);
  color: white;
  transform: translateY(-3px);
}

.contact-form {
  background: var(--color-bg-card);
  padding: var(--space-xl);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}

.form-group {
  margin-bottom: var(--space-lg);
}

.form-group label {
  display: block;
  margin-bottom: var(--space-sm);
  font-weight: 500;
  color: var(--color-text);
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: var(--space-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-bg);
  color: var(--color-text);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  font-family: inherit;
}

.form-group textarea {
  resize: vertical;
  min-height: 120px;
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.15);
}

/* ===== CTA SECTION ===== */
.cta-section {
  background: var(--gradient-primary);
  padding: var(--space-3xl) 0;
  text-align: center;
  color: white;
}

.cta-content h2 {
  font-family: var(--font-heading);
  font-size: var(--text-3xl);
  margin-bottom: var(--space-md);
}

.cta-content p {
  max-width: 600px;
  margin: 0 auto var(--space-xl);
  opacity: 0.95;
}

.newsletter-form {
  display: flex;
  max-width: 500px;
  margin: 0 auto;
  gap: var(--space-sm);
}

.newsletter-form input {
  flex: 1;
  padding: var(--space-md) var(--space-lg);
  border: none;
  border-radius: var(--radius-md);
  font-size: var(--text-base);
  outline: none;
}

.newsletter-form input:focus {
  box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.4);
}

.newsletter-form button {
  padding: var(--space-md) var(--space-xl);
  white-space: nowrap;
  background: white;
  color: var(--color-primary);
}

.newsletter-form button:hover {
  background: var(--color-bg-alt);
  color: var(--color-primary-dark);
}

/* ===== FOOTER ===== */
.footer {
  background: var(--color-bg-alt);
  padding: var(--space-3xl) 0 var(--space-lg);
  border-top: 1px solid var(--color-border);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-2xl);
  margin-bottom: var(--space-2xl);
}

.footer-brand .footer-logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--space-md);
}

.footer-brand .footer-logo i {
  color: var(--color-primary);
}

.footer-desc {
  color: var(--color-text-light);
  margin-bottom: var(--space-lg);
  font-size: var(--text-sm);
}

.footer-social {
  display: flex;
  gap: var(--space-sm);
}

.footer-social a {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  background: var(--color-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text);
  transition: all var(--transition-fast);
}

.footer-social a:hover {
  background: var(--color-primary);
  color: white;
  transform: translateY(-3px);
}

.footer-links h4 {
  font-weight: 600;
  margin-bottom: var(--space-lg);
  color: var(--color-text);
}

.footer-links ul li {
  margin-bottom: var(--space-sm);
}

.footer-links a {
  color: var(--color-text-light);
  font-size: var(--text-sm);
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border);
  flex-wrap: wrap;
  gap: var(--space-md);
}

.footer-bottom p {
  font-size: var(--text-sm);
  color: var(--color-text-light);
}

.footer-legal {
  display: flex;
  gap: var(--space-lg);
  flex-wrap: wrap;
}

.footer-legal a {
  font-size: var(--text-sm);
  color: var(--color-text-light);
}

.footer-legal a:hover {
  color: var(--color-primary);
}

/* ===== BACK TO TOP ===== */
.back-to-top {
  position: fixed;
  bottom: var(--space-lg);
  right: var(--space-lg);
  width: 48px;
  height: 48px;
  border-radius: var(--radius-full);
  background: var(--color-primary);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: all var(--transition-normal);
  z-index: var(--z-sticky);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--color-primary-dark);
  transform: translateY(-3px);
}

/* ===== ANIMATIONS ===== */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

.delay-1 { transition-delay: 100ms; }
.delay-2 { transition-delay: 200ms; }
.delay-3 { transition-delay: 300ms; }

/* ===== RESPONSIVE DESIGN ===== */
@media (min-width: 768px) {
  .about-grid,
  .contact-grid {
    grid-template-columns: 1fr 1fr;
  }

  .footer-grid {
    grid-template-columns: 2fr 1fr 1fr 1fr;
  }
}

@media (max-width: 767px) {
  .nav-menu {
    position: fixed;
    top: 70px;
    left: -100%;
    width: 100%;
    height: calc(100vh - 70px);
    background: var(--color-bg);
    flex-direction: column;
    align-items: flex-start;
    padding: var(--space-2xl);
    transition: left var(--transition-normal);
    box-shadow: var(--shadow-lg);
    overflow-y: auto;
    gap: var(--space-md);
  }

  .nav-menu.active {
    left: 0;
  }

  .nav-toggle {
    display: block;
  }

  .nav-cta {
    margin-top: var(--space-lg);
    width: 100%;
  }

  .nav-cta .btn {
    width: 100%;
  }

  .hero-title {
    font-size: var(--text-4xl);
  }

  .search-form {
    flex-direction: column;
  }

  .hero-stats {
    gap: var(--space-lg);
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }

  .footer-legal {
    justify-content: center;
  }

  .newsletter-form {
    flex-direction: column;
  }
}

@media (max-width: 480px) {
  .section {
    padding: var(--space-2xl) 0;
  }

  .section-title {
    font-size: var(--text-2xl);
  }

  .filters {
    flex-wrap: wrap;
  }

  .filter-btn {
    padding: var(--space-xs) var(--space-md);
    font-size: var(--text-xs);
  }

  .footer-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .footer-brand {
    display: flex;
    flex-direction: column;
    align-items: center;
  }

  .footer-links ul {
    display: flex;
    flex-direction: column;
    align-items: center;
  }

  .footer-social {
    justify-content: center;
  }
}

/* ===== ACCESSIBILITY ===== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* Focus visible for keyboard navigation */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
  :root {
    --color-border: #000;
    --color-shadow: rgba(0, 0, 0, 0.5);
  }
}