:root {
    --primary-color: #4361ee;
    --secondary-color: #3f37c9;
    --accent-color: #4cc9f0;
    --dark-color: #1a1a2e;
    --light-color: #f8f9fa;
    --success-color: #4bb543;
    --error-color: #ff3333;
    --border-radius: 12px;
    --box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
  }
  
  * {
    margin: 0;
    padding: 0;
    font-family: 'Poppins', sans-serif;
    box-sizing: border-box;
  }
  
  body {
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
    padding: 20px;
    display: flex;
    justify-content: center;
    align-items: center;
  }
  
  .container {
    width: 100%;
    max-width: 600px;
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    overflow: hidden;
    transition: var(--transition);
    position: relative;
  }
  
  .header {
    background: var(--primary-color);
    color: white;
    padding: 20px;
    text-align: center;
  }
  
  .header h1 {
    font-size: 28px;
    font-weight: 600;
  }
  
  .content {
    padding: 30px;
  }
  
  .input-group {
    margin-bottom: 20px;
  }
  
  .input-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--dark-color);
  }
  
  .input-field {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid #e0e0e0;
    border-radius: var(--border-radius);
    font-size: 16px;
    transition: var(--transition);
  }
  
  .input-field:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
  }
  
  .btn {
    display: inline-block;
    padding: 12px 24px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
    width: 100%;
  }
  
  .btn:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
  }
  
  .btn:active {
    transform: translateY(0);
  }
  
  .btn-secondary {
    background: white;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
  }
  
  .btn-secondary:hover {
    background: #f0f4ff;
  }
  
  #greeting {
    text-align: center;
    margin: 20px 0;
    font-size: 20px;
    color: var(--dark-color);
    animation: fadeIn 0.5s ease;
  }
  
  #quiz-container {
    display: none;
  }
  
  .question-container {
    margin-bottom: 25px;
  }
  
  .question-number {
    font-size: 14px;
    color: var(--primary-color);
    font-weight: 600;
    margin-bottom: 5px;
  }
  
  #question {
    font-size: 20px;
    font-weight: 500;
    color: var(--dark-color);
    margin-bottom: 20px;
    line-height: 1.4;
  }
  
  .answer-buttons {
    display: grid;
    grid-gap: 12px;
    margin-bottom: 20px;
  }
  
  .answer-btn {
    padding: 12px 20px;
    background: white;
    color: var(--dark-color);
    border: 2px solid #e0e0e0;
    border-radius: var(--border-radius);
    font-size: 16px;
    text-align: left;
    cursor: pointer;
    transition: var(--transition);
  }
  
  .answer-btn:hover {
    background: #f8f9fa;
    border-color: var(--primary-color);
  }
  
  .answer-btn.correct {
    background: var(--success-color);
    color: white;
    border-color: var(--success-color);
  }
  
  .answer-btn.incorrect {
    background: var(--error-color);
    color: white;
    border-color: var(--error-color);
  }
  
  .quiz-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 20px;
  }
  
  .score-display {
    font-weight: 600;
    color: var(--dark-color);
  }
  
  .progress-container {
    margin: 20px 0;
    background: #e0e0e0;
    border-radius: 10px;
    height: 8px;
    overflow: hidden;
  }
  
  .progress-bar {
    height: 100%;
    background: var(--primary-color);
    width: 0%;
    transition: width 0.4s ease;
  }
  
  .result-container {
    text-align: center;
    padding: 20px;
    display: none;
  }
  
  .result-icon {
    font-size: 60px;
    margin-bottom: 20px;
    color: var(--primary-color);
  }
  
  .result-text {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--dark-color);
  }
  
  .result-score {
    font-size: 18px;
    margin-bottom: 20px;
  }
  
  .footer {
    text-align: center;
    padding: 15px;
    font-size: 14px;
    color: #666;
    border-top: 1px solid #eee;
  }
  
  .footer a {
    color: var(--primary-color);
    text-decoration: none;
  }
  
  .footer a:hover {
    text-decoration: underline;
  }
  
  @keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
  }
  
  @media (max-width: 480px) {
    .content {
      padding: 20px;
    }
    
    #question {
      font-size: 18px;
    }
    
    .btn {
      padding: 10px 20px;
    }
  }