:root {
  --primary-color: #2563eb;
  --primary-dark: #1d4ed8;
  --secondary-color: #64748b;
  --success-color: #059669;
  --warning-color: #d97706;
  --danger-color: #dc2626;
  --text-primary: #1e293b;
  --text-secondary: #64748b;
  --text-light: #94a3b8;
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-tertiary: #f1f5f9;
  --border-color: #e2e8f0;
  --border-light: #f1f5f9;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
}

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

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

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1rem;
}

/* Navigation */
.navbar {
  background: var(--bg-primary);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 4rem;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--primary-color);
}

.nav-logo i {
  font-size: 1.5rem;
}

.nav-menu {
  display: flex;
  gap: 2rem;
}

.nav-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s ease;
}

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

.nav-toggle {
  display: none;
  flex-direction: column;
  cursor: pointer;
}

.nav-toggle span {
  width: 25px;
  height: 3px;
  background: var(--text-primary);
  margin: 3px 0;
  transition: 0.3s;
}

/* Hero Section */
.hero {
  background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
  padding: 4rem 0;
  min-height: 80vh;
  display: flex;
  align-items: center;
}

.hero-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1rem;
}

.hero-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
}

.hero-text h1 {
  font-size: 3rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1rem;
  line-height: 1.2;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--primary-color);
  font-weight: 600;
  margin-bottom: 1rem;
}

.hero-description {
  font-size: 1.1rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* Download Card */
.download-card {
  background: var(--bg-primary);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: 2rem;
  border: 1px solid var(--border-color);
}

.download-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.download-header i {
  font-size: 2rem;
  color: var(--primary-color);
}

.download-header h2 {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
}

.download-content p {
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
}

.download-btn {
  width: 100%;
  background: var(--primary-color);
  color: white;
  border: none;
  padding: 1rem 2rem;
  border-radius: var(--radius-md);
  font-size: 1.1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
}

.download-btn:hover {
  background: var(--primary-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

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

.download-btn:disabled {
  background: var(--text-light);
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

.download-status {
  margin-top: 1rem;
  padding: 0.75rem;
  border-radius: var(--radius-sm);
  font-weight: 500;
  display: none;
}

.download-status.success {
  background: #dcfdf7;
  color: var(--success-color);
  border: 1px solid #a7f3d0;
  display: block;
}

.download-status.error {
  background: #fef2f2;
  color: var(--danger-color);
  border: 1px solid #fca5a5;
  display: block;
}

.download-status.loading {
  background: #eff6ff;
  color: var(--primary-color);
  border: 1px solid #bfdbfe;
  display: block;
}

.download-info {
  margin-top: 1.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-light);
}

.download-info p {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  color: var(--text-light);
  margin-bottom: 0.5rem;
}

.download-info i {
  color: var(--success-color);
}

/* Instructions Section */
.instructions {
  padding: 4rem 0;
  background: var(--bg-primary);
}

.instructions h2 {
  text-align: center;
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 3rem;
}

.steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
}

.step {
  text-align: center;
  padding: 2rem 1rem;
}

.step-number {
  width: 4rem;
  height: 4rem;
  background: var(--primary-color);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  font-weight: 700;
  margin: 0 auto 1rem;
}

.step h3 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.step p {
  color: var(--text-secondary);
}

/* Security Section */
.security {
  padding: 4rem 0;
  background: var(--bg-secondary);
}

.security-content {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 4rem;
  align-items: center;
}

.security h2 {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 2rem;
}

.security-features {
  list-style: none;
}

.security-features li {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1rem;
  font-size: 1.1rem;
  color: var(--text-secondary);
}

.security-features i {
  color: var(--success-color);
  font-size: 1.25rem;
}

.security-icon {
  font-size: 8rem;
  color: var(--primary-color);
  opacity: 0.1;
}

/* Contact CTA */
.contact-cta {
  padding: 4rem 0;
  background: var(--primary-color);
  color: white;
}

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

.cta-content h2 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 1rem;
}

.cta-content p {
  font-size: 1.1rem;
  margin-bottom: 2rem;
  opacity: 0.9;
}

.cta-buttons {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-md);
  text-decoration: none;
  font-weight: 600;
  transition: all 0.2s ease;
  border: 2px solid transparent;
}

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

.btn-primary:hover {
  background: var(--bg-tertiary);
  transform: translateY(-1px);
}

.btn-secondary {
  background: transparent;
  color: white;
  border-color: white;
}

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

/* Footer */
.footer {
  background: var(--text-primary);
  color: white;
  padding: 3rem 0 1rem;
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1rem;
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-section h4 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.footer-section p {
  color: var(--text-light);
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.footer-bottom {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid var(--secondary-color);
  color: var(--text-light);
}

/* Error Page */
.error-page {
  min-height: 80vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 4rem 0;
}

.error-content {
  text-align: center;
}

.error-icon {
  font-size: 4rem;
  color: var(--warning-color);
  margin-bottom: 1rem;
}

.error-content h1 {
  font-size: 4rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.error-content h2 {
  font-size: 2rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.error-content p {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
}

.error-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* Responsive Design */
@media (max-width: 768px) {
  .nav-menu {
    display: none;
  }
  
  .nav-toggle {
    display: flex;
  }
  
  .hero-content {
    grid-template-columns: 1fr;
    gap: 2rem;
    text-align: center;
  }
  
  .hero-text h1 {
    font-size: 2rem;
  }
  
  .security-content {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .security-icon {
    font-size: 4rem;
  }
  
  .cta-buttons {
    flex-direction: column;
    align-items: center;
  }
  
  .steps {
    grid-template-columns: 1fr;
  }
  
  .container {
    padding: 0 0.5rem;
  }
}

@media (max-width: 480px) {
  .hero {
    padding: 2rem 0;
  }
  
  .hero-text h1 {
    font-size: 1.75rem;
  }
  
  .download-card {
    padding: 1.5rem;
  }
  
  .instructions,
  .security,
  .contact-cta {
    padding: 2rem 0;
  }
  
  .instructions h2 {
    font-size: 2rem;
  }
}