*, *::before, *::after {
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  }
  
  :root {
    --light-neutral: #339af0;
    --neutral: #1864ab;
    --correct: #2f9e44;
    --wrong: #e03131;
    --bg: #f0f4f8;
  }
  
  body {
    margin: 0;
    padding: 0;
    background-color: var(--neutral);
    color: #fff;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    transition: background-color 0.3s ease;
  }
  
  body.correct {
    background-color: var(--correct);
  }
  
  body.wrong {
    background-color: var(--wrong);
  }
  
  main {
    background-color: #fff;
    color: #000;
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.2);
    width: 90%;
    max-width: 600px;
    text-align: center;
  }
  
  h1 {
    color: var(--neutral);
    margin-bottom: 20px;
  }
  
  #question {
    font-size: 20px;
    margin-bottom: 20px;
  }
  
  #answer-buttons {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
    margin: 20px 0;
  }
  
  .btn {
    padding: 12px;
    border: 2px solid var(--neutral);
    border-radius: 8px;
    background-color: var(--light-neutral);
    color: #fff;
    font-size: 16px;
    cursor: pointer;
    transition: all 0.3s ease;
  }
  
  .btn:hover {
    background-color: #1c7ed6;
    border-color: #000;
  }
  
  .btn.correct {
    background-color: var(--correct);
    border-color: var(--correct);
  }
  
  .btn.wrong {
    background-color: var(--wrong);
    border-color: var(--wrong);
  }
  
  .start-btn, .next-btn {
    margin-top: 10px;
    font-weight: bold;
  }
  
  #controls {
    display: flex;
    justify-content: center;
    gap: 10px;
  }
  
  .hide {
    display: none;
  }