body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f0f2f5;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
  }
  
  .signup-form {
    width: 400px;
    background: white;
    padding: 30px 40px;
    border-radius: 15px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
  }
  
  .signup-form h2 {
    text-align: center;
    color: #333;
    margin-bottom: 30px;
  }
  
  .form-group {
    margin-bottom: 20px;
  }
  
  .form-group label {
    display: block;
    margin-bottom: 8px;
    color: #555;
    font-weight: bold;
  }
  
  .form-group input {
    width: 100%;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 8px;
    font-size: 14px;
    box-sizing: border-box;
  }
  
  .input-with-button {
    display: flex;
    gap: 10px;
  }
  
  .input-with-button input {
    flex: 1;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 8px;
    font-size: 14px;
    box-sizing: border-box;
  }
  
  .input-with-button button {
    padding: 10px 16px;
    background-color: #6c757d;
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 14px;
    white-space: nowrap;
  }
  
  .input-with-button button:hover {
    background-color: #5a6268;
  }
  
  #id-check-result {
    display: block;
    margin-top: 5px;
    font-size: 13px;
  }
  
  .signup-form button[type="submit"] {
    width: 100%;
    padding: 12px;
    background-color: #4285f4;
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    cursor: pointer;
    transition: background-color 0.2s;
  }
  
  .signup-form button[type="submit"]:disabled {
    background-color: #b0c4de;
    cursor: not-allowed;
  }
  
  .signup-form button[type="submit"]:hover:enabled {
    background-color: #357ae8;
  }
  