* {
      box-sizing: border-box;
      font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    }
    
    body {
      background-color: #1a1a2e;
      color: #e6e6e6;
      margin: 0;
      padding: 20px;
      display: flex;
      justify-content: center;
      align-items: center;
      min-height: 100vh;
      line-height: 1.5;
    }
    
    .container {
      background-color: #2d2d44;
      border-radius: 8px;
      padding: 25px 20px;
      width: 100%;
      max-width: 420px;
      box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    }
    
    h1 {
      text-align: center;
      margin-top: 0;
      margin-bottom: 20px;
      color: #ffcc66;
      font-weight: 600;
      font-size: clamp(1.5rem, 5vw, 1.8rem);
    }
    
    .form-group {
      position: relative;
      margin: 16px 0;
    }
    
    .form-input {
      width: 100%;
      padding: 16px 12px 6px;
      background: #3a3a52;
      border: 1px solid #555;
      border-radius: 4px;
      color: white;
      font-size: 16px; /* Prevents zoom on iOS */
      transition: border-color 0.2s;
      -webkit-appearance: none; /* Removes inner shadow on iOS */
    }
    
    .form-input:focus {
      outline: none;
      border-color: #ffcc66;
    }
    
    .form-label {
      position: absolute;
      left: 12px;
      top: 50%;
      transform: translateY(-50%);
      pointer-events: none;
      color: #bbb;
      transition: 0.2s;
      font-size: 16px;
    }
    
    .form-input:focus + .form-label,
    .form-input:not(:placeholder-shown) + .form-label {
      top: 8px;
      font-size: 12px;
      color: #ffcc66;
    }
    
    .password-container {
      position: relative;
    }
    
    .password-toggle {
      position: absolute;
      right: 12px;
      top: 50%;
      transform: translateY(-50%);
      cursor: pointer;
      font-size: 18px;
      color: #ccc;
      user-select: none;
      padding: 8px; /* Larger touch target */
      margin: -8px; /* Compensate for padding */
    }
    
    .btn {
      margin-top: 8px;
      padding: 12px 16px;
      background-color: #ffcc66;
      color: #2d2d44;
      border: none;
      border-radius: 4px;
      cursor: pointer;
      font-weight: 600;
      width: 100%;
      font-size: 16px;
      transition: background-color 0.2s;
      min-height: 44px; /* Minimum touch target size */
    }
    
    .btn:hover {
      background-color: #ffd580;
    }
    
    .btn:active {
      transform: scale(0.98); /* Touch feedback */
    }
    
    .signup-link {
      margin-top: 16px;
      font-size: 0.95em;
      color: #ddd;
      text-align: center;
    }
    
    .signup-link a {
      color: #ffcc66;
      text-decoration: none;
      padding: 4px 8px; /* Larger touch target */
      margin: -4px -8px; /* Compensate for padding */
      display: inline-block;
    }
    
    .signup-link a:hover {
      text-decoration: underline;
    }
    
    .return-link {
      margin-top: 20px;
      text-align: center;
    }
    
    .return-link a {
      color: #ffcc66;
      text-decoration: none;
      padding: 8px 12px;
      margin: -8px -12px;
      display: inline-block;
    }
    
    .return-link a:hover {
      text-decoration: underline;
    }
    
    .error-message {
      color: #ff6b6b;
      font-size: 14px;
      margin-top: 4px;
      display: none;
    }
    
    .password-strength {
      height: 4px;
      margin-top: 8px;
      border-radius: 2px;
      background-color: #3a3a52;
      overflow: hidden;
    }
    
    .password-strength-bar {
      height: 100%;
      width: 0%;
      transition: width 0.3s, background-color 0.3s;
    }
    
    .required::after {
      content: " *";
      color: #ff6b6b;
    }
    
    /* Mobile-specific optimizations */
    @media (max-width: 480px) {
      body {
        padding: 15px 10px;
        align-items: flex-start; /* Better for very small screens */
        padding-top: 20px;
      }
      
      .container {
        padding: 20px 15px;
        border-radius: 6px;
      }
      
      .form-group {
        margin: 14px 0;
      }
      
      .form-input {
        padding: 14px 10px 6px;
      }
      
      .btn {
        padding: 14px 16px; /* Larger touch target on mobile */
      }
    }
    
    @media (max-width: 360px) {
      .container {
        padding: 15px 12px;
      }
      
      h1 {
        font-size: 1.4rem;
      }
    }
    
    /* Prevent zoom on iOS for inputs */
    @media (max-width: 480px) {
      input, select, textarea {
        font-size: 16px !important;
      }
    }