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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  line-height: 1.6;
  color: #333;
  background: #f8f9fa;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

header {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  padding: 3rem 0;
  text-align: center;
}

header h1 {
  font-size: 3rem;
  margin-bottom: 1rem;
}

header p {
  font-size: 1.2rem;
  opacity: 0.9;
}

main {
  padding: 4rem 0;
}

.hero {
  text-align: center;
  margin-bottom: 4rem;
}

.hero h2 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  color: #2563eb;
}

.hero p {
  font-size: 1.2rem;
  color: #666;
  margin-bottom: 2rem;
}

.converter-section {
  background: white;
  margin: 2rem 0;
  border-radius: 1rem;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  overflow: hidden;
}

.converter-header {
  background: #2563eb;
  color: white;
  padding: 1rem 2rem;
}

.converter-header h3 {
  font-size: 1.5rem;
  font-weight: bold;
}

.upload-section {
  padding: 2rem;
}

.upload-area {
  border: 2px dashed #2563eb;
  border-radius: 8px;
  padding: 3rem;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s ease;
}

.upload-area:hover {
  background: #f0f9ff;
  border-color: #1d4ed8;
}

.upload-area.drag-over {
  background: #dbeafe;
  border-color: #1d4ed8;
}

.upload-icon {
  font-size: 3rem;
  margin-bottom: 1rem;
}

.upload-area h3 {
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
  color: #2563eb;
}

.upload-area p {
  color: #666;
  margin-bottom: 0.5rem;
}

.upload-formats {
  font-size: 0.9rem;
  color: #999;
}

.settings-panel {
  padding: 2rem;
  border-top: 1px solid #e5e7eb;
}

.settings-panel h3 {
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  color: #1f2937;
}

.settings-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
}

.setting-group {
  display: flex;
  flex-direction: column;
}

.setting-group label {
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: #374151;
}

.setting-group select {
  padding: 0.5rem;
  border: 1px solid #d1d5db;
  border-radius: 4px;
  font-size: 1rem;
}

.files-section {
  padding: 2rem;
  border-top: 1px solid #e5e7eb;
}

.files-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

.files-header h3 {
  font-size: 1.5rem;
  color: #1f2937;
}

.btn-clear {
  background: #ef4444;
  color: white;
  border: none;
  padding: 0.5rem 1rem;
  border-radius: 4px;
  cursor: pointer;
}

.btn-clear:hover {
  background: #dc2626;
}

.files-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1rem;
}

.file-item {
  border: 1px solid #e5e7eb;
  border-radius: 8px;
  padding: 1rem;
  background: white;
}

.file-preview {
  width: 100%;
  height: 120px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #f9fafb;
  border-radius: 4px;
  margin-bottom: 0.5rem;
}

.file-preview img {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
}

.file-info {
  text-align: center;
}

.file-name {
  font-weight: 600;
  margin-bottom: 0.25rem;
  word-break: break-all;
}

.file-size {
  font-size: 0.875rem;
  color: #666;
  margin-bottom: 0.5rem;
}

.file-status {
  font-size: 0.875rem;
}

.file-status .processing {
  color: #f59e0b;
}

.file-status .error {
  color: #ef4444;
}

.file-status .success {
  color: #10b981;
}

.btn-remove {
  background: #ef4444;
  color: white;
  border: none;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0.5rem auto 0;
}

.convert-section {
  padding: 2rem;
  border-top: 1px solid #e5e7eb;
  text-align: center;
}

.btn-convert {
  background: #10b981;
  color: white;
  border: none;
  padding: 1rem 2rem;
  border-radius: 8px;
  font-size: 1.1rem;
  font-weight: bold;
  cursor: pointer;
  transition: all 0.2s;
}

.btn-convert:hover:not(:disabled) {
  background: #059669;
  transform: translateY(-2px);
}

.btn-convert:disabled {
  background: #9ca3af;
  cursor: not-allowed;
}

.progress-info {
  margin-top: 1rem;
}

.progress-bar {
  width: 100%;
  height: 8px;
  background: #e5e7eb;
  border-radius: 4px;
  overflow: hidden;
  margin-bottom: 0.5rem;
}

.progress-fill {
  height: 100%;
  background: #10b981;
  transition: width 0.3s ease;
}

.result-section {
  padding: 2rem;
  border-top: 1px solid #e5e7eb;
}

.result-success {
  text-align: center;
  padding: 2rem;
  background: #f0fdf4;
  border-radius: 8px;
  border: 1px solid #bbf7d0;
}

.result-success h3 {
  color: #059669;
  margin-bottom: 1rem;
}

.result-actions {
  margin-top: 1.5rem;
}

.btn-download, .btn-new {
  background: #2563eb;
  color: white;
  border: none;
  padding: 0.75rem 1.5rem;
  border-radius: 4px;
  margin: 0 0.5rem;
  cursor: pointer;
}

.btn-download:hover, .btn-new:hover {
  background: #1d4ed8;
}

.features {
  margin: 2rem 0;
  padding: 2rem;
  background: white;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.features h3 {
  font-size: 2rem;
  text-align: center;
  margin-bottom: 3rem;
  color: #1f2937;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}

.feature {
  background: white;
  padding: 2rem;
  border-radius: 1rem;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  text-align: center;
}

.feature h4 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
  color: #1f2937;
}

.feature p {
  color: #6b7280;
  line-height: 1.6;
}

.how-to-use {
  margin: 2rem 0;
  padding: 2rem;
  background: #f0f9ff;
  border-radius: 8px;
}

.how-to-use h3 {
  color: #333;
  margin-bottom: 2rem;
  font-size: 1.5rem;
  text-align: center;
}

.how-to-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  max-width: 900px;
  margin: 0 auto;
}

.how-to-step {
  background: white;
  padding: 2rem;
  border-radius: 12px;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
  text-align: center;
  position: relative;
}

.step-number {
  position: absolute;
  top: -15px;
  left: 50%;
  transform: translateX(-50%);
  width: 30px;
  height: 30px;
  background: #2563eb;
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  font-size: 1.1rem;
}

.how-to-step h4 {
  color: #2563eb;
  margin: 1rem 0 0.5rem 0;
  font-size: 1.2rem;
}

.how-to-step p {
  color: #666;
  line-height: 1.6;
}

.faq {
  margin: 2rem 0;
  padding: 2rem;
  background: #f8f9fa;
  border-radius: 8px;
}

.faq h3 {
  color: #333;
  margin-bottom: 1.5rem;
  font-size: 1.5rem;
}

.faq-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
}

.faq-item {
  background: white;
  padding: 1.5rem;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.faq-item h4 {
  color: #2563eb;
  margin-bottom: 0.5rem;
  font-size: 1.1rem;
}

.faq-item p {
  color: #666;
  line-height: 1.6;
}

.usage {
  margin: 2rem 0;
  padding: 2rem;
  background: #e0f2fe;
  border-radius: 8px;
  border-left: 4px solid #2563eb;
}

.usage h3 {
  color: #333;
  margin-bottom: 1rem;
  font-size: 1.5rem;
}

.usage-content p {
  color: #555;
  line-height: 1.8;
  margin-bottom: 1rem;
}

.usage-content p:last-child {
  margin-bottom: 0;
}

footer {
  background: #f9fafb;
  padding: 2rem;
  text-align: center;
  color: #6b7280;
  border-top: 1px solid #e5e7eb;
}

@media (max-width: 768px) {
  header h1 {
    font-size: 2rem;
  }
  
  .hero h2 {
    font-size: 2rem;
  }
  
  .feature-grid {
    grid-template-columns: 1fr;
  }
  
  .how-to-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }
  
  .faq-grid {
    grid-template-columns: 1fr;
  }
  
  .how-to-step {
    padding: 1.5rem;
  }
  
  .faq-item {
    padding: 1rem;
  }
  
  .usage {
    padding: 1.5rem;
  }
  
  .how-to-use {
    padding: 1.5rem;
  }
  
  .faq {
    padding: 1.5rem;
  }
}

@media (max-width: 480px) {
  header h1 {
    font-size: 1.5rem;
  }
  
  .hero h2 {
    font-size: 1.5rem;
  }
  
  .hero p {
    font-size: 0.9rem;
  }
  
  .feature h4 {
    font-size: 1rem;
  }
  
  .feature p {
    font-size: 0.9rem;
  }
  
  .how-to-step h4 {
    font-size: 1rem;
  }
  
  .how-to-step p {
    font-size: 0.9rem;
  }
  
  .faq-item h4 {
    font-size: 1rem;
  }
  
  .faq-item p {
    font-size: 0.9rem;
  }
  
  .usage-content p {
    font-size: 0.9rem;
  }
}