/* ===================================
   CSS Variables & Theming
   =================================== */
:root {
  /* Colors */
  --color-primary: #006B54;
  --color-primary-hover: #005544;
  --color-primary-light: #e6f2ef;
  
  /* Light Mode (default) */
  --color-background: #ffffff;
  --color-background-secondary: #f8faf9;
  --color-surface: #ffffff;
  --color-surface-elevated: #ffffff;
  --color-text: #1a1a1a;
  --color-text-secondary: #666666;
  --color-text-muted: #999999;
  --color-border: #e5e5e5;
  --color-border-light: #f0f0f0;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.1);
  --shadow-card: 0 2px 8px rgba(0, 0, 0, 0.04), 0 8px 24px rgba(0, 0, 0, 0.06);
  
  /* 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;
  --spacing-4xl: 6rem;
  
  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;
}

/* Dark Mode */
[data-theme="dark"] {
  --color-background: #0a0a0a;
  --color-background-secondary: #111111;
  --color-surface: #1a1a1a;
  --color-surface-elevated: #222222;
  --color-text: #f5f5f5;
  --color-text-secondary: #a0a0a0;
  --color-text-muted: #666666;
  --color-border: #2a2a2a;
  --color-border-light: #1f1f1f;
  --color-primary-light: #0d2b24;
  
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.4);
  --shadow-card: 0 2px 8px rgba(0, 0, 0, 0.2), 0 8px 24px rgba(0, 0, 0, 0.3);
}

/* ===================================
   Reset & Base Styles
   =================================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-background);
  transition: background-color var(--transition-base), color var(--transition-base);
}

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

a {
  color: inherit;
  text-decoration: none;
}

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

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

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ===================================
   Animations
   =================================== */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

/* ===================================
   Header & Navigation
   =================================== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background-color: var(--color-background);
  border-bottom: 1px solid var(--color-border-light);
  transition: background-color var(--transition-base), border-color var(--transition-base);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  gap: var(--spacing-lg);
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-weight: 600;
  font-size: 1.125rem;
  color: var(--color-text);
  transition: opacity var(--transition-fast);
}

.logo:hover {
  opacity: 0.8;
}

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

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

.nav-links a {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  transition: color var(--transition-fast);
}

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

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  color: var(--color-text-secondary);
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.theme-toggle:hover {
  background-color: var(--color-background-secondary);
  color: var(--color-text);
}

.icon-moon {
  display: none;
}

[data-theme="dark"] .icon-sun {
  display: none;
}

[data-theme="dark"] .icon-moon {
  display: block;
}

@media (min-width: 768px) {
  .nav-links {
    display: flex;
  }
}

/* ===================================
   Buttons
   =================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-lg);
  font-size: 0.9375rem;
  font-weight: 500;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.btn-primary {
  background-color: var(--color-primary);
  color: #ffffff;
}

.btn-primary:hover {
  background-color: var(--color-primary-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-secondary {
  background-color: var(--color-surface);
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

.btn-secondary:hover {
  background-color: var(--color-background-secondary);
  border-color: var(--color-text-muted);
  transform: translateY(-2px);
}

.btn-large {
  padding: var(--spacing-lg) var(--spacing-xl);
  font-size: 1rem;
  border-radius: var(--radius-lg);
}

.btn-large span {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  line-height: 1.3;
}

.btn-large small {
  font-size: 0.75rem;
  font-weight: 400;
  opacity: 0.8;
}

.btn-large strong {
  font-size: 1.125rem;
}

/* ===================================
   Hero Section
   =================================== */
.hero {
  padding: calc(72px + var(--spacing-4xl)) 0 var(--spacing-4xl);
  background-color: var(--color-background);
  overflow: hidden;
}

.hero-content {
  display: grid;
  gap: var(--spacing-3xl);
  align-items: center;
}

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

.hero-title {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
  color: var(--color-text);
  margin-bottom: var(--spacing-lg);
  text-wrap: balance;
}

.hero-description {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--color-text-secondary);
  max-width: 540px;
  margin: 0 auto var(--spacing-xl);
  line-height: 1.7;
}

.hero-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-md);
  justify-content: center;
}

/* Hero Mockup */
.hero-visual {
  display: flex;
  justify-content: center;
}

.mockup {
  position: relative;
  width: 100%;
  max-width: 500px;
}

.mockup-desktop {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--spacing-sm);
  box-shadow: var(--shadow-card);
  border: 1px solid var(--color-border);
}

.mockup-screen {
  background: var(--color-background-secondary);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.mockup-bar {
  display: flex;
  gap: 6px;
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border-light);
}

.mockup-bar span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--color-border);
}

.mockup-bar span:first-child {
  background: #ff5f57;
}

.mockup-bar span:nth-child(2) {
  background: #ffbd2e;
}

.mockup-bar span:nth-child(3) {
  background: #28ca41;
}

.mockup-content {
  padding: var(--spacing-xl);
}

.mockup-line {
  height: 12px;
  background: var(--color-border);
  border-radius: 6px;
  margin-bottom: var(--spacing-md);
  width: 80%;
}

.mockup-line.short {
  width: 50%;
}

.mockup-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-md);
  margin-top: var(--spacing-xl);
}

.mockup-box {
  height: 60px;
  background: var(--color-primary-light);
  border-radius: var(--radius-sm);
}

.mockup-phone {
  position: absolute;
  bottom: -20px;
  right: -20px;
  width: 120px;
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 6px;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--color-border);
}

.mockup-phone-screen {
  background: var(--color-background-secondary);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  min-height: 180px;
}

.phone-notch {
  width: 40%;
  height: 4px;
  background: var(--color-border);
  border-radius: 2px;
  margin: 0 auto var(--spacing-md);
}

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

.phone-cursor {
  width: 16px;
  height: 16px;
  border: 2px solid var(--color-primary);
  border-radius: 50%;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% {
    transform: scale(1);
    opacity: 1;
  }
  50% {
    transform: scale(1.2);
    opacity: 0.7;
  }
}

.phone-controls {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-sm);
  width: 100%;
}

.control-circle {
  width: 50px;
  height: 50px;
  border: 2px solid var(--color-border);
  border-radius: 50%;
  background: var(--color-primary-light);
}

.control-buttons {
  display: flex;
  gap: var(--spacing-sm);
}

.control-buttons span {
  width: 30px;
  height: 20px;
  background: var(--color-border);
  border-radius: 4px;
}

.connection-line {
  position: absolute;
  top: 50%;
  right: 60px;
  transform: translateY(-50%) rotate(-30deg);
}

@media (min-width: 768px) {
  .hero-content {
    grid-template-columns: 1fr 1fr;
    text-align: left;
  }
  
  .hero-text {
    text-align: left;
  }
  
  .hero-description {
    margin-left: 0;
  }
  
  .hero-buttons {
    justify-content: flex-start;
  }
  
  .mockup-phone {
    width: 140px;
    bottom: -30px;
    right: -40px;
  }
  
  .mockup-phone-screen {
    min-height: 220px;
  }
}

/* ===================================
   Features Section
   =================================== */
.features {
  padding: var(--spacing-4xl) 0;
  background-color: var(--color-background-secondary);
}

.section-title {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  text-align: center;
  margin-bottom: var(--spacing-md);
  letter-spacing: -0.02em;
}

.section-subtitle {
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  text-align: center;
  margin-bottom: var(--spacing-3xl);
}

/* Features Diagram */
.features-diagram {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-3xl);
  flex-wrap: wrap;
}

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

.diagram-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 88px;
  height: 88px;
  border-radius: var(--radius-xl);
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.diagram-icon:hover {
  transform: scale(1.05);
  box-shadow: var(--shadow-lg);
}

.diagram-icon-windows {
  color: #0078d4;
}

.diagram-icon-android {
  color: #3ddc84;
}

.diagram-label {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--color-text);
}

.diagram-connector {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-xs);
}

.connector-line {
  width: 40px;
  height: 2px;
  background: linear-gradient(90deg, var(--color-border), var(--color-primary), var(--color-border));
  border-radius: 1px;
}

.connector-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: var(--color-primary-light);
  color: var(--color-primary);
  border-radius: var(--radius-full);
}

.connector-label {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

@media (max-width: 639px) {
  .features-diagram {
    gap: var(--spacing-md);
  }
  
  .diagram-icon {
    width: 72px;
    height: 72px;
  }
  
  .diagram-icon svg {
    width: 32px;
    height: 32px;
  }
  
  .connector-line {
    width: 24px;
  }
}

.features-grid {
  display: grid;
  gap: var(--spacing-lg);
}

.feature-card {
  background: var(--color-surface);
  padding: var(--spacing-xl);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border-light);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card);
}

.feature-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background: var(--color-primary-light);
  color: var(--color-primary);
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-lg);
}

.feature-card h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

.feature-card p {
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

@media (min-width: 640px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .features-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

/* ===================================
   How It Works Section
   =================================== */
.how-it-works {
  padding: var(--spacing-4xl) 0;
  background-color: var(--color-background);
}

.steps {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
  max-width: 800px;
  margin: 0 auto;
}

.step {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-lg);
  background: var(--color-surface);
  padding: var(--spacing-xl);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border-light);
}

.step-number {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background: var(--color-primary);
  color: #ffffff;
  font-size: 1.25rem;
  font-weight: 700;
  border-radius: var(--radius-full);
  flex-shrink: 0;
}

.step-content h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
}

.step-content p {
  color: var(--color-text-secondary);
  font-size: 0.9375rem;
}

.step-connector {
  display: none;
}

@media (min-width: 768px) {
  .steps {
    flex-direction: row;
    align-items: flex-start;
    gap: var(--spacing-md);
  }
  
  .step {
    flex-direction: column;
    text-align: center;
    flex: 1;
    align-items: center;
  }
  
  .step-connector {
    display: block;
    width: 60px;
    height: 2px;
    background: var(--color-border);
    margin-top: 48px;
    flex-shrink: 0;
  }
}

/* ===================================
   Download Section
   =================================== */
.download {
  padding: var(--spacing-4xl) 0;
  background-color: var(--color-background-secondary);
}

.download-card {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-hover) 100%);
  padding: var(--spacing-3xl) var(--spacing-xl);
  border-radius: var(--radius-xl);
  text-align: center;
  color: #ffffff;
}

.download-card h2 {
  font-size: clamp(1.5rem, 4vw, 2rem);
  font-weight: 700;
  margin-bottom: var(--spacing-md);
}

.download-card p {
  font-size: 1.125rem;
  opacity: 0.9;
  max-width: 500px;
  margin: 0 auto var(--spacing-xl);
}

.download-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-md);
  justify-content: center;
}

.download-buttons .btn-primary {
  background-color: #ffffff;
  color: var(--color-primary);
}

.download-buttons .btn-primary:hover {
  background-color: #f0f0f0;
}

.download-buttons .btn-secondary {
  background-color: transparent;
  color: #ffffff;
  border-color: rgba(255, 255, 255, 0.4);
}

.download-buttons .btn-secondary:hover {
  background-color: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.6);
}

@media (min-width: 768px) {
  .download-card {
    padding: var(--spacing-4xl) var(--spacing-3xl);
  }
}

/* ===================================
   Footer
   =================================== */
.footer {
  background-color: var(--color-background);
  border-top: 1px solid var(--color-border-light);
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-xl);
  padding: var(--spacing-3xl) var(--spacing-lg);
  text-align: center;
}

.footer-brand .logo {
  justify-content: center;
  margin-bottom: var(--spacing-sm);
}

.footer-brand p {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
}

.footer-links {
  display: flex;
  gap: var(--spacing-lg);
}

.footer-links a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  color: var(--color-text-secondary);
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

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

.footer-bottom {
  border-top: 1px solid var(--color-border-light);
  padding: var(--spacing-lg);
  text-align: center;
}

.footer-bottom p {
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

@media (min-width: 768px) {
  .footer-content {
    flex-direction: row;
    justify-content: space-between;
    text-align: left;
  }
  
  .footer-brand .logo {
    justify-content: flex-start;
  }
}