/* ========================================
   CSS Reset & Base Styles
   ======================================== */

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

:root {
  /* Color Scheme: Aviation Blue with Cloud White */
  --primary-blue: #4A90E2;
  --primary-blue-dark: #357ABD;
  --primary-blue-light: #6BA3E8;
  --accent-orange: #FF9B4A;
  --accent-yellow: #FFD54A;
  --accent-green: #66BB6A;
  --accent-purple: #AB47BC;
  --accent-cyan: #26C6DA;
  
  --cloud-white: #FFFFFF;
  --sky-light: #F5F9FC;
  --sky-medium: #E8F1F8;
  --text-dark: #1A2332;
  --text-medium: #4A5568;
  --text-light: #5A6575;
  
  /* Coming Soon Button */
  --neutral-gray: #2a2a2a;
  
  /* Typography */
  --font-system: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", "Monaco", "Inconsolata", "Roboto Mono", "Courier New", monospace;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  
  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.5rem;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  
  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
  --spring: cubic-bezier(0.34, 1.56, 0.64, 1);
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 64px;
}

body {
  font-family: var(--font-system);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-dark);
  background-color: var(--cloud-white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

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

a:active {
  color: var(--primary-blue);
}

button {
  font-family: inherit;
  cursor: pointer;
}

/* ========================================
   Container & Layout
   ======================================== */

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

/* ========================================
   Header (Sticky Navigation)
   ======================================== */

.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 48px;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--sky-medium);
  z-index: 1000;
  transition: box-shadow var(--transition-base);
}

.header.scrolled {
  box-shadow: var(--shadow-md);
}

.header-container {
  max-width: 1200px;
  margin: 0 auto;
  height: 100%;
  padding: 0 var(--spacing-lg);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.header-left {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.header-icon {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-md);
}

.header-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-dark);
  display: none;
}

.header-nav {
  display: none;
  align-items: center;
  gap: var(--spacing-lg);
}

.nav-link {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-medium);
  transition: color var(--transition-fast);
}

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

.nav-cta {
  padding: var(--spacing-sm) var(--spacing-lg);
  background: var(--primary-blue);
  color: var(--cloud-white);
  border-radius: var(--radius-lg);
  font-size: 0.875rem;
  font-weight: 600;
  transition: all var(--transition-base) var(--spring);
}

.nav-cta:hover {
  background: var(--primary-blue-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.nav-cta:active {
  transform: translateY(0);
}

.header-cta-mobile {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: var(--primary-blue);
  color: var(--cloud-white);
  border-radius: 50%;
  transition: all var(--transition-base) var(--spring);
}

.header-cta-mobile:hover {
  background: var(--primary-blue-dark);
  transform: scale(1.05);
}

.header-cta-mobile:active {
  transform: scale(0.95);
}

/* ========================================
   Hero Section
   ======================================== */

.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding-top: 48px;
  overflow: hidden;
}

.hero-background {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.hero-bg-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    to bottom,
    rgba(245, 249, 252, 0.92) 0%,
    rgba(245, 249, 252, 0.88) 50%,
    rgba(245, 249, 252, 0.92) 100%
  );
}

.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  padding: var(--spacing-2xl) var(--spacing-lg);
  max-width: 600px;
  margin: 0 auto;
}

.hero-icon {
  width: 96px;
  height: 96px;
  margin: 0 auto var(--spacing-lg);
  border-radius: var(--radius-2xl);
  box-shadow: var(--shadow-xl);
  animation: float 3s ease-in-out infinite;
}

@keyframes float {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-10px);
  }
}

.hero-title {
  font-size: 2rem;
  font-weight: 700;
  line-height: 1.2;
  color: var(--text-dark);
  margin-bottom: var(--spacing-md);
  letter-spacing: -0.02em;
}

.hero-subtitle {
  font-size: 1.125rem;
  line-height: 1.6;
  color: var(--text-medium);
  margin-bottom: var(--spacing-2xl);
}

/* ========================================
   Download Buttons
   ======================================== */

.download-buttons {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
  align-items: center;
}

.download-btn {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  padding: var(--spacing-md) var(--spacing-xl);
  background: var(--text-dark);
  color: var(--cloud-white);
  border: none;
  border-radius: var(--radius-lg);
  font-size: 1rem;
  font-weight: 600;
  min-height: 56px;
  width: 100%;
  max-width: 280px;
  transition: all var(--transition-base) var(--spring);
  cursor: pointer;
  box-shadow: var(--shadow-md);
}

.download-btn:hover {
  transform: translateY(-4px) scale(1.02);
  box-shadow: var(--shadow-xl);
  background: var(--primary-blue-dark);
}

.download-btn:active {
  transform: translateY(-2px) scale(1);
}

.download-btn.google-play {
  background: var(--text-dark);
}

.download-btn.google-play:hover {
  background: #0d1117;
}

.download-btn.app-store {
  position: relative;
  background: var(--neutral-gray);
  opacity: 0.55;
  filter: grayscale(0.6);
  cursor: not-allowed;
}

.download-btn.app-store:hover {
  transform: none;
  box-shadow: var(--shadow-md);
  background: var(--neutral-gray);
}

.btn-icon {
  flex-shrink: 0;
}

.btn-text {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.125rem;
}

.btn-label {
  font-size: 0.625rem;
  font-weight: 400;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  opacity: 0.9;
}

.btn-store {
  font-size: 1.125rem;
  font-weight: 600;
  line-height: 1;
}

.coming-soon-badge {
  position: absolute;
  top: -8px;
  right: -8px;
  background: var(--accent-orange);
  color: var(--cloud-white);
  font-size: 0.625rem;
  font-weight: 700;
  padding: 0.25rem 0.5rem;
  border-radius: var(--radius-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  box-shadow: var(--shadow-md);
}

/* ========================================
   Features Section
   ======================================== */

.features {
  padding: var(--spacing-3xl) 0;
  background: var(--sky-light);
}

.section-title {
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  color: var(--text-dark);
  margin-bottom: var(--spacing-md);
  letter-spacing: -0.02em;
}

.section-subtitle {
  font-size: 1.125rem;
  text-align: center;
  color: var(--text-medium);
  margin-bottom: var(--spacing-2xl);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.features-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-lg);
}

.feature-card {
  background: var(--cloud-white);
  padding: var(--spacing-xl);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base) var(--spring);
  opacity: 0;
  transform: translateY(20px);
}

.feature-card.visible {
  opacity: 1;
  transform: translateY(0);
}

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

.feature-icon {
  margin-bottom: var(--spacing-lg);
}

.feature-title {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-dark);
  margin-bottom: var(--spacing-sm);
}

.feature-description {
  font-size: 1rem;
  line-height: 1.6;
  color: var(--text-medium);
}

/* ========================================
   Download CTA Section
   ======================================== */

.download-cta {
  padding: var(--spacing-3xl) 0;
  background: linear-gradient(135deg, var(--primary-blue) 0%, var(--primary-blue-dark) 100%);
  color: var(--cloud-white);
  text-align: center;
}

.cta-title {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: var(--spacing-md);
  letter-spacing: -0.02em;
}

.cta-subtitle {
  font-size: 1.125rem;
  margin-bottom: var(--spacing-2xl);
  opacity: 0.95;
}

.download-buttons.large .download-btn {
  max-width: 320px;
}

.download-buttons.large .download-btn.large {
  min-height: 64px;
}

.download-buttons.large .btn-icon {
  width: 32px;
  height: 32px;
}

/* ========================================
   About Section
   ======================================== */

.about {
  padding: var(--spacing-3xl) 0;
  background: var(--cloud-white);
}

.about-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-xl);
  max-width: 800px;
  margin: 0 auto;
}

.about-icon {
  width: 80px;
  height: 80px;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-md);
}

.about-text {
  text-align: center;
}

.about-text p {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--text-medium);
  margin-bottom: var(--spacing-lg);
}

.about-text p:last-child {
  margin-bottom: 0;
}

.about-contact {
  font-size: 1rem;
  color: var(--text-medium);
}

.about-contact a {
  color: var(--primary-blue);
  font-weight: 600;
}

/* ========================================
   Footer
   ======================================== */

.footer {
  padding: var(--spacing-2xl) 0;
  background: var(--text-dark);
  color: var(--sky-medium);
  text-align: center;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
}

.footer-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
}

.footer-name {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--cloud-white);
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
}

.footer-links a {
  font-size: 0.875rem;
  color: var(--sky-medium);
  transition: color var(--transition-fast);
}

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

.footer-contact {
  margin-bottom: var(--spacing-lg);
}

.footer-contact p {
  font-size: 0.875rem;
}

.footer-contact a {
  color: var(--primary-blue-light);
}

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

.footer-copyright {
  font-size: 0.875rem;
  opacity: 0.7;
}

/* ========================================
   Mobile Sticky CTA
   ======================================== */

.mobile-sticky-cta {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  padding: var(--spacing-md);
  background: rgba(255, 255, 255, 0.98);
  backdrop-filter: blur(10px);
  border-top: 1px solid var(--sky-medium);
  box-shadow: 0 -4px 6px -1px rgba(0, 0, 0, 0.1);
  z-index: 999;
  transform: translateY(100%);
  transition: transform var(--transition-base);
}

.mobile-sticky-cta.visible {
  transform: translateY(0);
}

.sticky-cta-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  width: 100%;
  padding: var(--spacing-md);
  background: var(--primary-blue);
  color: var(--cloud-white);
  border: none;
  border-radius: var(--radius-lg);
  font-size: 1rem;
  font-weight: 600;
  min-height: 48px;
  box-shadow: var(--shadow-md);
  transition: all var(--transition-base) var(--spring);
}

.sticky-cta-btn:hover {
  background: var(--primary-blue-dark);
  transform: scale(1.02);
}

.sticky-cta-btn:active {
  transform: scale(0.98);
}

/* ========================================
   Responsive Design (Tablet & Desktop)
   ======================================== */

@media (min-width: 768px) {
  .header {
    height: 64px;
  }
  
  .header-title {
    display: block;
  }
  
  .header-nav {
    display: flex;
  }
  
  .header-cta-mobile {
    display: none;
  }
  
  .hero-title {
    font-size: 3rem;
  }
  
  .hero-subtitle {
    font-size: 1.25rem;
  }
  
  .download-buttons {
    flex-direction: row;
    justify-content: center;
  }
  
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-xl);
  }
  
  .cta-title {
    font-size: 2.5rem;
  }
  
  .about-content {
    flex-direction: row;
    text-align: left;
  }
  
  .about-text {
    text-align: left;
  }
  
  .mobile-sticky-cta {
    display: none;
  }
}

@media (min-width: 1024px) {
  .features-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .hero-icon {
    width: 120px;
    height: 120px;
  }
  
  .hero-title {
    font-size: 3.5rem;
  }
}

/* ========================================
   Accessibility & Motion Preferences
   ======================================== */

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  
  .hero-icon {
    animation: none;
  }
}

/* Focus styles for keyboard navigation */
a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--primary-blue);
  outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
  .hero-overlay {
    background: rgba(245, 249, 252, 0.95);
  }
  
  .download-btn {
    border: 2px solid currentColor;
  }
}