:root {
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --background: #ffffff;
    --foreground: #000000;
    --muted: #6b7280;
    --border: #e5e7eb;
  }
  
  * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  }
  
  body {
    background: radial-gradient(
      circle at center,
      rgba(37, 99, 235, 0.1) 0%,
      rgba(37, 99, 235, 0) 100%
    );
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
  }
  
  .navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border);
    z-index: 1000;
  }
  
  .navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 4rem;
    padding: 0 2rem;
    max-width: 1200px;
    margin: 0 auto;
  }
  
  .back-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--muted);
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 500;
    transition: color 0.2s;
  }
  
  .back-link:hover {
    color: var(--foreground);
  }
  
  .auth-container {
    width: 100%;
    max-width: 480px;
    padding: 2rem;
    perspective: 1000px;
    margin-top: 2rem;
  }
  
  .auth-card {
    background: var(--background);
    border-radius: 1rem;
    padding: 2rem;
    box-shadow: 
      0 4px 6px -1px rgba(0, 0, 0, 0.1),
      0 2px 4px -1px rgba(0, 0, 0, 0.06);
    transform-origin: center;
    animation: cardIn 0.6s cubic-bezier(0.16, 1, 0.3, 1);
  }
  
  .logo {
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 2rem;
  }
  
  .logo img {
    width: 48px;
    height: 48px;
  }
  
  .logo-text {
    font-size: 28px;
    font-weight: 600;
    margin-left: 0.5rem;
  }
  
  .auth-form h1 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    text-align: center;
  }
  
  .auth-form p {
    text-align: center;
    color: var(--muted);
    margin-bottom: 2rem;
    font-size: 0.875rem;
  }
  
  .form-group {
    margin-bottom: 1.25rem;
    position: relative;
  }
  
  .form-group .icon {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--muted);
    pointer-events: none;
    transition: color 0.2s;
  }
  
  .form-group input:focus + .icon {
    color: var(--primary);
  }
  
  .password-toggle {
    position: absolute;
    right: 1rem;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    color: var(--muted);
    cursor: pointer;
    padding: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: color 0.2s;
  }
  
  .password-toggle svg {
    margin-left: -20px !important;
  }
  
  .password-toggle:hover {
    color: var(--foreground);
  }
  
  .form-group input {
    width: 100%;
    padding: 0.875rem 1rem 0.875rem 3rem;
    border: 1px solid var(--border);
    border-radius: 0.75rem;
    font-size: 0.875rem;
    transition: all 0.2s;
    background: transparent;
  }
  
  .form-group input[type="password"] {
    padding-right: 3rem;
  }
  
  .form-group input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
  }
  
  .auth-button {
    width: 100%;
    padding: 0.875rem;
    background-color: var(--primary);
    color: white;
    border: none;
    border-radius: 0.75rem;
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    position: relative;
    overflow: hidden;
  }
  
  .auth-button::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 300%;
    height: 300%;
    background: radial-gradient(circle, rgba(255,255,255,0.2) 0%, transparent 60%);
    transform: translate(-50%, -50%) scale(0);
    transition: transform 0.5s;
  }
  
  .auth-button:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
  }
  
  .auth-button:hover::after {
    transform: translate(-50%, -50%) scale(1);
  }
  
  .auth-button .arrow {
    width: 1.25rem;
    height: 1.25rem;
    transition: transform 0.2s;
  }
  
  .auth-button:hover .arrow {
    transform: translateX(4px);
  }

.auth-button:disabled {
  background-color: #9ca3af;
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

.auth-button:disabled:hover {
  background-color: #9ca3af;
  transform: none;
}

.auth-button:disabled:hover::after {
  transform: translate(-50%, -50%) scale(0);
}

.auth-button:disabled .arrow {
  transform: none;
}

  .auth-footer {
    margin-top: 1.5rem;
    text-align: center;
    font-size: 0.875rem;
    color: var(--muted);
  }

    p.message {
      display: block;
      background: linear-gradient(to right, #f8fafc, #f1f5f9);
      border-left: 3px solid var(--primary);
      padding: 1rem 1.25rem;
      margin: 1.25rem 0;
      font-size: 0.925rem;
      line-height: 1.5;
      color: var(--foreground);
      animation: messageSlideIn 0.3s ease-out;
    }

    @keyframes messageSlideIn {
      from {
        opacity: 0;
        transform: translateY(-8px);
      }
      to {
        opacity: 1;
        transform: translateY(0);
      }
    }

  .auth-footer a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
    position: relative;
  }
  
  .auth-footer a::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 100%;
    height: 1px;
    background: currentColor;
    transform: scaleX(0);
    transform-origin: right;
    transition: transform 0.3s ease;
  }
  
  .auth-footer a:hover::after {
    transform: scaleX(1);
    transform-origin: left;
  }
  
  @keyframes cardIn {
    from {
      opacity: 0;
      transform: translateY(20px) rotateX(-10deg);
    }
    to {
      opacity: 1;
      transform: translateY(0) rotateX(0);
    }
  }
  
  .form-group input {
    transform-origin: left;
    animation: inputIn 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    animation-fill-mode: both;
  }
  
  .form-group:nth-child(1) input { animation-delay: 0.1s; }
  .form-group:nth-child(2) input { animation-delay: 0.2s; }
  .form-group:nth-child(3) input { animation-delay: 0.3s; }
  
  @keyframes inputIn {
    from {
      opacity: 0;
      transform: translateX(-20px);
    }
    to {
      opacity: 1;
      transform: translateX(0);
    }
  }
  
  .payment-container {
    width: 100%;
    max-width: 480px;
    padding: 2rem;
  }
  
  .payment-card {
    background: var(--background);
    border-radius: 1rem;
    padding: 2rem;
    box-shadow: 
      0 4px 6px -1px rgba(0, 0, 0, 0.1),
      0 2px 4px -1px rgba(0, 0, 0, 0.06);
    animation: cardIn 0.6s cubic-bezier(0.16, 1, 0.3, 1);
  }
  
  .payment-details {
    margin: 2rem 0;
    text-align: center;
  }
  
  .payment-details h2 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--foreground);
  }
  
  .payment-details p {
    color: var(--muted);
    margin-bottom: 1.5rem;
  }
  
  .payment-amount {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 0.5rem;
  }
  
  .payment-email {
    color: var(--muted);
    font-size: 0.875rem;
  }
  
  .btn {
    width: 100%;
    padding: 0.875rem;
    border: none;
    border-radius: 0.75rem;
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    position: relative;
    overflow: hidden;
  }
  
  .btn-primary {
    background-color: var(--primary);
    color: white;
  }
  
  .btn-primary:not(:disabled):hover {
    background-color: var(--primary-hover);
  }
  
  .btn-secondary {
    background-color: transparent;
    border: 1px solid var(--border);
    color: var(--foreground);
    margin-top: 0.5rem;
  }
  
  .btn-secondary:hover {
    background-color: rgba(0, 0, 0, 0.05);
  }
  
  .progress-bar {
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    background-color: rgba(255, 255, 255, 0.2);
    width: 0%;
    transition: width 0.1s linear;
  }
  
  .w-100 { width: 100%; }
  .mt-2 { margin-top: 0.5rem; }
  .mt-3 { margin-top: 1rem; }
  
  @media (max-width: 480px) {
    .auth-container,
    .payment-container {
      padding: 1rem;
    }
    
    .auth-card,
    .payment-card {
      padding: 1.5rem;
    }
  }