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

  body {
      font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
      background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
      min-height: 100vh;
      color: #333;
  }

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

  .header {
      text-align: center;
      margin-bottom: 40px;
      color: white;
  }

  .header h1 {
      font-size: 3rem;
      margin-bottom: 10px;
      text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
  }

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

  .main-content {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 30px;
      margin-bottom: 30px;
  }

  .upload-section,
  .output-section {
      background: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(10px);
      border-radius: 20px;
      padding: 30px;
      box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
      border: 1px solid rgba(255, 255, 255, 0.2);
  }

  .section-title {
      font-size: 1.5rem;
      margin-bottom: 20px;
      color: #4a5568;
      display: flex;
      align-items: center;
      gap: 10px;
  }

  .upload-area {
      border: 3px dashed #cbd5e0;
      border-radius: 15px;
      padding: 40px 20px;
      text-align: center;
      transition: all 0.3s ease;
      cursor: pointer;
      background: #f7fafc;
  }

  .upload-area:hover {
      border-color: #667eea;
      background: #edf2f7;
      transform: translateY(-2px);
  }

  .upload-area.dragover {
      border-color: #667eea;
      background: #e6fffa;
      transform: scale(1.02);
  }

  .upload-icon {
      font-size: 3rem;
      color: #a0aec0;
      margin-bottom: 15px;
  }

  .upload-text {
      color: #4a5568;
      font-size: 1.1rem;
      margin-bottom: 15px;
  }

  .file-input {
      display: none;
  }

  .btn {
      background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
      color: white;
      border: none;
      padding: 12px 24px;
      border-radius: 25px;
      cursor: pointer;
      font-size: 1rem;
      transition: all 0.3s ease;
      display: inline-flex;
      align-items: center;
      gap: 8px;
  }

  .btn:hover {
      transform: translateY(-2px);
      box-shadow: 0 10px 20px rgba(102, 126, 234, 0.4);
  }

  .btn:disabled {
      opacity: 0.6;
      cursor: not-allowed;
      transform: none;
  }

  .output-area {
      background: #1a202c;
      color: #e2e8f0;
      border-radius: 10px;
      padding: 20px;
      font-family: 'Courier New', monospace;
      font-size: 14px;
      line-height: 1.5;
      max-height: 400px;
      overflow-y: auto;
      border: 1px solid #2d3748;
  }

  .improvements-list {
      background: #f0fff4;
      border-radius: 10px;
      padding: 20px;
      margin-top: 20px;
      border-left: 4px solid #38a169;
  }

  .improvement-item {
      display: flex;
      align-items: center;
      gap: 10px;
      margin-bottom: 10px;
      padding: 8px;
      background: white;
      border-radius: 8px;
      box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  }

  .improvement-icon {
      color: #38a169;
      font-size: 1.2rem;
  }

  .stats {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
      gap: 20px;
      margin-top: 30px;
  }

  .stat-card {
      background: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(10px);
      border-radius: 15px;
      padding: 20px;
      text-align: center;
      box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
  }

  .stat-number {
      font-size: 2rem;
      font-weight: bold;
      color: #667eea;
  }

  .stat-label {
      color: #4a5568;
      margin-top: 5px;
  }

  .loading {
      display: none;
      text-align: center;
      color: #667eea;
  }

  .loading.show {
      display: block;
  }

  .spinner {
      border: 3px solid #f3f3f3;
      border-top: 3px solid #667eea;
      border-radius: 50%;
      width: 40px;
      height: 40px;
      animation: spin 1s linear infinite;
      margin: 0 auto 15px;
  }

  @keyframes spin {
      0% {
          transform: rotate(0deg);
      }

      100% {
          transform: rotate(360deg);
      }
  }

  @media (max-width: 768px) {
      .main-content {
          grid-template-columns: 1fr;
      }

      .header h1 {
          font-size: 2rem;
      }
  }

  .visually-hidden {
      position: absolute;
      left: -9999px;
      top: auto;
      width: 1px;
      height: 1px;
      overflow: hidden;
  }