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

:root {
  --primary-color: #6366f1;
  --primary-hover: #4f46e5;
  --secondary-color: #8b5cf6;
  --background: #ffffff;
  --surface: #f8fafc;
  --text-primary: #1e293b;
  --text-secondary: #64748b;
  --border-color: #e2e8f0;
  --success-color: #10b981;
  --error-color: #ef4444;
  --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);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
    'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
    sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background: var(--background);
  color: var(--text-primary);
  line-height: 1.6;
}

/* Landing Page Styles */
.landing-page {
  min-height: 100vh;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem 1rem;
}

.container {
  width: 100%;
  max-width: 900px;
  margin: 0 auto;
}

.header {
  text-align: center;
  margin-bottom: 3rem;
  color: white;
}

.title {
  font-size: 3rem;
  font-weight: 700;
  margin-bottom: 1rem;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.subtitle {
  font-size: 1.25rem;
  opacity: 0.95;
  font-weight: 300;
}

.main-content {
  background: white;
  border-radius: 24px;
  padding: 3rem;
  box-shadow: var(--shadow-xl);
}

.upload-area {
  border: 3px dashed var(--border-color);
  border-radius: 16px;
  padding: 4rem 2rem;
  text-align: center;
  transition: all 0.3s ease;
  background: var(--surface);
  cursor: pointer;
}

.upload-area.dragging {
  border-color: var(--primary-color);
  background: rgba(99, 102, 241, 0.05);
  transform: scale(1.02);
}

.upload-area.has-file {
  border-color: var(--success-color);
  background: rgba(16, 185, 129, 0.05);
  padding: 2rem;
}

.file-input {
  display: none;
}

.upload-icon {
  color: var(--primary-color);
  margin-bottom: 1.5rem;
}

.upload-title {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.upload-subtitle {
  color: var(--text-secondary);
  margin: 1rem 0;
}

.browse-button {
  background: var(--primary-color);
  color: white;
  border: none;
  padding: 0.75rem 2rem;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  margin: 1rem 0;
}

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

.upload-hint {
  color: var(--text-secondary);
  font-size: 0.875rem;
  margin-top: 1rem;
}

.file-preview {
  display: flex;
  align-items: center;
  gap: 1rem;
  background: white;
  padding: 1.5rem;
  border-radius: 12px;
  margin-bottom: 2rem;
  box-shadow: var(--shadow-sm);
}

.file-icon {
  color: var(--error-color);
  flex-shrink: 0;
}

.file-info {
  flex: 1;
  text-align: left;
}

.file-name {
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
  word-break: break-all;
}

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

.remove-file {
  background: none;
  border: none;
  font-size: 2rem;
  color: var(--text-secondary);
  cursor: pointer;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  transition: all 0.2s ease;
  flex-shrink: 0;
}

.remove-file:hover {
  background: var(--surface);
  color: var(--error-color);
}

.convert-button {
  width: 100%;
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
  color: white;
  border: none;
  padding: 1rem 2rem;
  border-radius: 12px;
  font-size: 1.125rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: var(--shadow-lg);
}

.convert-button:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: var(--shadow-xl);
}

.convert-button:disabled {
  opacity: 0.7;
  cursor: not-allowed;
}

.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 2rem;
  margin-top: 3rem;
  padding-top: 3rem;
  border-top: 1px solid var(--border-color);
}

.feature {
  text-align: center;
}

.feature-icon {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.feature h3 {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

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

/* Conversion Page Styles */
.conversion-page {
  min-height: 100vh;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem 1rem;
}

.conversion-card {
  text-align: center;
  padding: 2rem 0;
}

.spinner-container {
  margin-bottom: 2rem;
}

.spinner {
  width: 64px;
  height: 64px;
  border: 4px solid var(--border-color);
  border-top-color: var(--primary-color);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin: 0 auto;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

.success-icon {
  color: var(--success-color);
  margin-bottom: 1.5rem;
}

.error-icon {
  color: var(--error-color);
  margin-bottom: 1.5rem;
}

.status-title {
  font-size: 1.75rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

.status-title.success {
  color: var(--success-color);
}

.status-title.error {
  color: var(--error-color);
}

.status-message {
  color: var(--text-secondary);
  font-size: 1rem;
  margin-bottom: 1.5rem;
}

.file-name-display {
  background: var(--surface);
  padding: 1rem;
  border-radius: 8px;
  margin: 1.5rem 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.file-label {
  font-weight: 600;
  color: var(--text-secondary);
  font-size: 0.875rem;
}

.download-actions {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-top: 2rem;
}

.download-button {
  padding: 1rem 2rem;
  border: none;
  border-radius: 12px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: var(--shadow-md);
}

.download-button.primary {
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
  color: white;
}

.download-button.primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.download-button.secondary {
  background: white;
  color: var(--primary-color);
  border: 2px solid var(--primary-color);
}

.download-button.secondary:hover {
  background: var(--primary-color);
  color: white;
  transform: translateY(-2px);
}

.retry-button {
  background: var(--primary-color);
  color: white;
  border: none;
  padding: 0.75rem 2rem;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  margin-top: 1rem;
}

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

.info-section {
  margin-top: 3rem;
  padding-top: 3rem;
  border-top: 1px solid var(--border-color);
}

.info-section h3 {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 1.5rem;
  text-align: center;
}

.info-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
}

.info-card {
  background: var(--surface);
  padding: 1.5rem;
  border-radius: 12px;
  text-align: center;
  transition: all 0.2s ease;
}

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

.info-icon {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.info-card h4 {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

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

@media (max-width: 768px) {
  .title {
    font-size: 2rem;
  }

  .subtitle {
    font-size: 1rem;
  }

  .main-content {
    padding: 2rem 1.5rem;
  }

  .upload-area {
    padding: 3rem 1.5rem;
  }

  .features {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .download-actions {
    width: 100%;
  }

  .download-button {
    width: 100%;
  }

  .info-cards {
    grid-template-columns: 1fr;
  }
}