body {
    font-family: Arial, sans-serif;
    text-align: center;
    margin: 0;
    background: #f0f8ff;
    color: #333;
    overflow: hidden;
  }
  
  #game-container {
    margin: 20px auto;
    width: 90vw;
    max-width: 800px;
    padding: 20px;
    border: 2px solid #333;
    border-radius: 10px;
    background: #fff;
    position: relative;
    overflow: hidden;
    height: 600px;
  }
  
  #circle {
    position: absolute;
    width: 70px;
    height: 70px;
    background: red;
    border-radius: 50%;
    display: none;
    cursor: pointer;
  }
  
  #power-up {
    position: absolute;
    width: 50px;
    height: 50px;
    background: gold;
    border-radius: 50%;
    display: none;
    cursor: pointer;
    box-shadow: 0 0 15px 5px rgba(255, 223, 0, 0.7);
  }
  
  #start-btn, .difficulty-btn {
    margin-top: 20px;
    padding: 15px 30px;
    font-size: 18px;
    background: #28a745;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
  }
  
  #start-btn:hover, .difficulty-btn:hover {
    background: #218838;
  }
  
  #scoreboard {
    position: absolute;
    top: 10px;
    right: 10px;
    font-size: 18px;
    text-align: right;
    display: none;
  }
  
  h1 {
    margin-bottom: 10px;
  }
  
  .hidden {
    display: none;
  }
  
  .difficulty-btn {
    margin: 5px;
    padding: 10px 20px;
    font-size: 16px;
    background: #007bff;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
  }
  
  .difficulty-btn:hover {
    background: #0056b3;
  }