:root {
      --primary: #667eea;
      --primary-dark: #5a67d8;
      --secondary: #764ba2;
      --success: #10b981;
      --error: #ef4444;
      --warning: #f59e0b;
      --gray-100: #f7fafc;
      --gray-200: #edf2f7;
      --gray-300: #e2e8f0;
      --gray-500: #718096;
      --gray-700: #4a5568;
      --gray-900: #2d3748;
      --shadow: 0 10px 25px rgba(0,0,0,0.1);
      --shadow-lg: 0 15px 35px rgba(0,0,0,0.15);
      --transition: all 0.3s ease;
    }
    
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    
    html, body {
      height: 100%;
      font-family: 'Poppins', sans-serif;
      background: linear-gradient(135deg, var(--secondary), var(--primary));
      background-attachment: fixed;
      color: var(--gray-900);
      overflow-x: hidden;
    }
    
    body {
      display: flex;
      justify-content: center;
      align-items: center;
      padding: 20px;
    }
    
    .container {
      width: 100%;
      max-width: 480px;
      margin: 0 auto;
    }
    
    .card {
      background: white;
      border-radius: 20px;
      padding: 40px 35px;
      width: 100%;
      box-shadow: var(--shadow-lg);
      text-align: center;
      position: relative;
      overflow: hidden;
      z-index: 1;
    }
    
    .card::before {
      content: '';
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      height: 6px;
      background: linear-gradient(90deg, var(--secondary), var(--primary));
      z-index: 2;
    }
    
    .logo {
      width: 80px;
      height: 80px;
      background: linear-gradient(135deg, var(--primary), var(--secondary));
      border-radius: 20px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 25px;
      box-shadow: 0 5px 15px rgba(118, 75, 162, 0.3);
    }
    
    .logo i {
      font-size: 36px;
      color: white;
    }
    
    h1 {
      font-size: 28px;
      font-weight: 700;
      margin-bottom: 8px;
      color: var(--gray-900);
      letter-spacing: -0.5px;
    }
    
    .subtitle {
      font-size: 16px;
      color: var(--gray-500);
      margin-bottom: 30px;
      line-height: 1.5;
      max-width: 350px;
      margin-left: auto;
      margin-right: auto;
    }
    
    .form-group {
      margin-bottom: 24px;
      text-align: left;
    }
    
    label {
      display: block;
      margin-bottom: 8px;
      font-weight: 500;
      color: var(--gray-700);
      font-size: 14px;
    }
    
    .input-with-icon {
      position: relative;
    }
    
    .input-with-icon i {
      position: absolute;
      left: 16px;
      top: 50%;
      transform: translateY(-50%);
      color: var(--gray-500);
      font-size: 18px;
    }
    
    input[type="text"] {
      width: 100%;
      padding: 16px 16px 16px 48px;
      font-size: 16px;
      border: 2px solid var(--gray-200);
      border-radius: 12px;
      background: var(--gray-100);
      transition: var(--transition);
      font-weight: 500;
      color: var(--gray-900);
    }
    
    input[type="text"]:focus {
      outline: none;
      border-color: var(--primary);
      box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.15);
    }
    
    input[type="text"]::placeholder {
      color: var(--gray-500);
      font-weight: 400;
    }
    
    button {
      width: 100%;
      background: linear-gradient(to right, var(--primary), var(--secondary));
      color: white;
      padding: 17px;
      font-size: 17px;
      font-weight: 600;
      border: none;
      border-radius: 12px;
      cursor: pointer;
      transition: var(--transition);
      position: relative;
      overflow: hidden;
      box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
    }
    
    button:hover {
      transform: translateY(-2px);
      box-shadow: 0 7px 20px rgba(102, 126, 234, 0.5);
    }
    
    button:active {
      transform: translateY(0);
    }
    
    .spinner {
      display: none;
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
    }
    
    .spinner .fa-spinner {
      animation: spin 1s linear infinite;
    }
    
    @keyframes spin {
      0% { transform: rotate(0deg); }
      100% { transform: rotate(360deg); }
    }
    
    button .text {
      display: block;
      transition: opacity 0.3s ease;
    }
    
    button.loading .text {
      opacity: 0;
    }
    
    button.loading .spinner {
      display: block;
    }
    
    .example {
      display: block;
      text-decoration: none;
      background: var(--gray-100);
      color: var(--gray-700);
      padding: 14px;
      border-radius: 12px;
      font-size: 14px;
      font-weight: 500;
      margin-top: 20px;
      transition: var(--transition);
      border: 2px dashed var(--gray-200);
    }
    
    .example:hover {
      background: var(--gray-200);
      border-color: var(--gray-300);
    }
    
    .example i {
      margin-right: 8px;
      color: var(--primary);
    }
    
    .modal {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: rgba(0, 0, 0, 0.7);
      z-index: 1000;
      justify-content: center;
      align-items: center;
      opacity: 0;
      transition: opacity 0.3s ease;
    }
    
    .modal.active {
      display: flex;
      opacity: 1;
    }
    
    .modal-content {
      background: white;
      border-radius: 20px;
      width: 90%;
      max-width: 400px;
      box-shadow: var(--shadow-lg);
      overflow: hidden;
      transform: translateY(30px);
      transition: transform 0.4s ease;
    }
    
    .modal.active .modal-content {
      transform: translateY(0);
    }
    
    .modal-header {
      padding: 25px 25px 15px;
      text-align: center;
      position: relative;
    }
    
    .modal-icon {
      width: 70px;
      height: 70px;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 15px;
      font-size: 32px;
      color: white;
    }
    
    .success .modal-icon {
      background: var(--success);
      box-shadow: 0 5px 15px rgba(16, 185, 129, 0.3);
    }
    
    .error .modal-icon {
      background: var(--error);
      box-shadow: 0 5px 15px rgba(239, 68, 68, 0.3);
    }
    
    .warning .modal-icon {
      background: var(--warning);
      box-shadow: 0 5px 15px rgba(245, 158, 11, 0.3);
    }
    
    .modal-title {
      font-size: 22px;
      font-weight: 700;
      margin-bottom: 8px;
    }
    
    .modal-body {
      padding: 0 25px 25px;
      text-align: center;
    }
    
    .modal-message {
      color: var(--gray-700);
      font-size: 16px;
      line-height: 1.5;
      margin-bottom: 25px;
    }
    
    .modal-button {
      background: linear-gradient(to right, var(--primary), var(--secondary));
      color: white;
      padding: 14px;
      font-size: 16px;
      font-weight: 600;
      border: none;
      border-radius: 12px;
      cursor: pointer;
      width: 100%;
      transition: var(--transition);
      box-shadow: 0 5px 15px rgba(102, 126, 234, 0.3);
    }
    
    .modal-button:hover {
      transform: translateY(-2px);
      box-shadow: 0 7px 20px rgba(102, 126, 234, 0.4);
    }
    
    .countdown {
      font-size: 14px;
      color: var(--gray-500);
      margin-top: 15px;
      display: block;
    }
    
    footer {
      text-align: center;
      color: rgba(255, 255, 255, 0.7);
      margin-top: 30px;
      font-size: 14px;
    }
    
    footer a {
      color: white;
      text-decoration: none;
      font-weight: 500;
    }
    
    footer a:hover {
      text-decoration: underline;
    }
    
    @media (max-width: 480px) {
      .card {
        padding: 30px 25px;
      }
      
      h1 {
        font-size: 24px;
      }
      
      .subtitle {
        font-size: 15px;
      }
    }