html {
    scroll-behavior: smooth;
  }
  
  body {
    background: linear-gradient(to right, #f2f2f2, #e8e3d9);
    font-family: 'Segoe UI', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
  }
  
  .login-container {
    background: white;
    border-radius: 10px;
    padding: 40px;
    box-shadow: 0 0 20px rgba(0,0,0,0.1);
    width: 360px;
    position: relative;
    z-index: 10;
  }
  
  .logo {
    text-align: center;
    margin-bottom: 20px;
  }
  
  .logo img {
    height: 80px;
  }
  
  .logo h2 {
    font-size: 24px;
    color: blue;
    letter-spacing: 2px;
  }
  
  .login-container input,
  .login-container select {
    width: 100%;
    padding: 10px;
    margin: 10px 0 20px 0;
    border: 1px solid #ccc;
    border-radius: 5px;
  }
  
  .login-container button {
    width: 100%;
    background-color: lightblue;
    color: white;
    padding: 10px;
    border: none;
    border-radius: 5px;
    font-weight: bold;
    cursor: pointer;
  }
  
  .login-container button:hover {
    background-color: blue;
  }
  
  .register-link {
    text-align: center;
    margin-top: 15px;
  }
  
  .register-link a {
    color: blue;
    text-decoration: none;
    font-size: 14px;
  }
  
  .register-link a:hover {
    text-decoration: underline;
  }
  
  /* ローディング画面 */
  #loading-overlay {
    display: none;
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background-color: rgba(255, 255, 255, 0.9);
    z-index: 999;
    justify-content: center;
    align-items: center;
    flex-direction: column;
  }
  
  .spinner {
    width: 50px;
    height: 50px;
    border: 6px solid rgba(0, 0, 128, 0.2);  /* navyの薄い背景 */
    border-top: 6px solid #000080 !important; /* ネイビー強制指定 */
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 20px;
  }
  
  @keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
  }
  
  #loading-overlay p {
    font-size: 18px;
    color: navy;
  }