body {
    font-family: Arial;
    display: flex;
    margin: 0;
    background-color: #1e1e1e;
    color: #ddd;
}

  .sidebar {
    width: 220px;
    background: #2c2c2c;
    color: white;
    padding: 20px;
    box-shadow: 2px 0 5px rgba(0, 0, 0, 0.3);
  }

  .sidebar h3 {
    color: #f0f0f0;
    margin-bottom: 15px;
  }

  .sidebar button {
    background: #fff;
    color: #222;
    border: none;
    padding: 10px 18px;
    margin-bottom: 12px;
    cursor: pointer;
    width: auto;
    min-width: 160px;
    text-align: left;
    border-radius: 8px;
    box-shadow: 0 1px 6px rgba(0,0,0,0.07);
    display: block;
    margin-left: auto;
    margin-right: auto;
    transition: background 0.2s, color 0.2s;
  }

  .sidebar button:hover {
    background-color: #4db8ff;
    color: #fff;
  }

  .main {
    flex: 1;
    padding: 20px;
  }

  /* Centrar el botón Corregir */
  #contenido > button,
  .main > button {
    display: block;
    margin: 30px auto 0 auto;
    text-align: center;
  }

  .question {
    margin-bottom: 25px;
    padding: 15px;
    background: #2b2b2b;
    border-radius: 8px;
    border-left: 5px solid #444;
  }

  .option {
    margin: 5px 0;
  }

  .correct {
    color: #28e07f;
    font-weight: bold;
  }

  .incorrect {
    color: #ff4c4c;
    font-weight: bold;
  }

  h2, h3, h4 {
    color: #f8f8f8;
  }

  button {
    background-color: #444;
    color: white;
    border: none;
    padding: 10px 20px;
    cursor: pointer;
    border-radius: 6px;
  }

  button:hover {
    background-color: #555;
  }

  a.volver {
    display: block;
    margin-top: 30px;
    color: #4db8ff;
    text-decoration: none;
  }

  a.volver:hover {
    text-decoration: underline;
  }

  input[type="radio"] {
  transform: scale(1.2); 
  margin-right: 8px;     
  cursor: pointer;
}

/* Oculta el botón hamburguesa en escritorio y muestra en móvil */
.menu-btn {
  display: none;
}

/* Sidebar siempre visible en escritorio */
.sidebar {
  width: 200px;
  float: left;
  min-height: 100vh;
}

/* Main con margen en escritorio */
.main {
  margin-left: 220px;
  padding: 20px;
}

/* --- Responsive para móvil --- */
  @media (max-width: 768px) {
    .menu-btn {
      display: block;
      position: fixed;
      top: 10px;
      left: 10px;
      z-index: 1100;
      background: #4db8ff;
      color: #fff;
      border: none;
      font-size: 2em;
      padding: 5px 15px;
      border-radius: 5px;
    }
    .sidebar {
      position: fixed;
      left: -220px;
      top: 0;
      width: 220px;
      height: auto;
      background: transparent;
      transition: left 0.3s;
      z-index: 1000;
      float: none;
      min-height: unset;
      padding-top: 60px;
      opacity: 0;
      pointer-events: none;
    }
    .sidebar.open {
      left: 0;
      opacity: 1;
      pointer-events: auto;
      background: transparent;
    }
    .sidebar h3 {
      text-align: center;
      color: #222;
    }
    .sidebar button {
      background: #fff;
      color: #222;
      width: 90%;
      margin-left: auto;
      margin-right: auto;
      margin-bottom: 14px;
      box-shadow: 0 1px 6px rgba(0,0,0,0.07);
    }
    .sidebar button:hover {
      background: #4db8ff;
      color: #fff;
    }
    .main {
      margin-left: 0 !important;
      padding: 10px;
    }
    .main h2 {
      text-align: center;
    }
    #contenido > button,
    .main > button {
      display: block;
      margin: 30px auto 0 auto;
      text-align: center;
    }
  }