:root {
      --loading-bg-color: #f3efef;
      --loading-color: #0e0e0e;
      --loading-subtitle-color: #3b3939;
      --primary-color: #4a6cf7;
      --secondary-color: #6c757d;
      --success-color: #28a745;
      --card-bg: #ffffff;
      --text-color: #333333;
      --border-radius: 12px;
      --box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    }

    @media (prefers-color-scheme: dark) {
      :root {
        --loading-bg-color: #242323;
        --loading-color: #f3efef;
        --loading-subtitle-color: #9d9999;
        --card-bg: #1e1e1e;
        --text-color: #f0f0f0;
        --box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
      }
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    body {
      font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
      background: linear-gradient(135deg, #f4f6f9 90%, #59aef8 10%);
      color: var(--text-color);
      line-height: 1.6;
      min-height: 100vh;
      padding: 20px;
      transition: background 0.3s ease;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
    }

    header {
      text-align: center;
      padding: 40px 0;
    }

    h1 {
      font-size: 3.5rem;
      margin-bottom: 10px;
      background: linear-gradient(90deg, var(--primary-color), #9c2be2);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      text-fill-color: transparent;
    }

    .subtitle {
      font-size: 1.2rem;
      color: var(--secondary-color);
      max-width: 600px;
      margin: 0 auto 30px;
    }

    .card-container {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
      gap: 25px;
      margin-top: 30px;
    }

    .card {
      background: var(--card-bg);
      border-radius: var(--border-radius);
      padding: 30px;
      box-shadow: var(--box-shadow);
      transition: transform 0.3s ease, box-shadow 0.3s ease;
      display: flex;
      flex-direction: column;
      min-height: 100%;
    }

    .card:hover {
      transform: translateY(-10px);
      box-shadow: 0 15px 40px rgba(0, 0, 0, 0.15);
    }

    .card h2 {
      background: linear-gradient(90deg, var(--primary-color), #9726dc);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      text-fill-color: transparent;
      margin-bottom: 15px;
      font-size: 1.8rem;
    }

    .card p {
      margin-bottom: -5px;
      color: var(--secondary-color);
    }

    .card .price {
      font-size: 1.1rem;
      font-weight: 600;
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .card .original-price {
      color: var(--secondary-color);
      opacity: 0.7;
    }

    .card .current-price {
      color: var(--primary-color);
      font-size: 1.2rem;
    }

    .feature-list {
      list-style-type: none;
      margin: 20px 0;
    }

    .feature-list li {
      padding: 10px 0;
      border-bottom: 1px solid rgba(0, 0, 0, 0.05);
      display: flex;
      align-items: center;
    }

    .feature-list li:before {
      content: "✓";
      color: var(--success-color);
      font-weight: bold;
      margin-right: 10px;
    }

    .btn {
      display: inline-block;
      background: var(--primary-color);
      color: white;
      padding: 12px 25px;
      border-radius: 50px;
      text-decoration: none;
      font-weight: 600;
      transition: all 0.3s ease;
      border: none;
      cursor: pointer;
      margin-top: auto;
      align-self: flex-start;
    }

    .btn:hover {
      background: #3a5bd0;
      transform: translateY(-2px);
      box-shadow: 0 5px 15px rgba(74, 108, 247, 0.4);
    }

    .loading-container {
      background: var(--loading-bg-color);
      color: var(--loading-color);
      position: fixed;
      left: 0;
      right: 0;
      top: 0;
      bottom: 0;
      z-index: 9999;
      display: flex;
      justify-content: center;
      align-items: center;
      transition: opacity 0.5s ease;
    }

    .loading-box {
      text-align: center;
      display: flex;
      justify-content: center;
      flex-direction: column;
      align-items: center;
    }

    .loading {
      margin: 20px;
      position: relative;
      width: 1px;
      height: 1px;
    }

    .loading:before,
    .loading:after {
      position: absolute;
      display: inline-block;
      width: 15px;
      height: 15px;
      content: "";
      border-radius: 100%;
      background-color: var(--loading-color);
    }

    .loading:before {
      left: -15px;
      animation: ball-pulse infinite 0.75s -0.4s cubic-bezier(0.2, 0.68, 0.18, 1.08);
    }

    .loading:after {
      right: -15px;
      animation: ball-pulse infinite 0.75s cubic-bezier(0.2, 0.68, 0.18, 1.08);
    }

    @keyframes ball-pulse {
      0% {
        transform: scale(1);
        opacity: 1;
      }

      50% {
        transform: scale(0.1);
        opacity: 0.6;
      }

      100% {
        transform: scale(1);
        opacity: 1;
      }
    }

    .loading-text {
      margin-top: 20px;
      font-size: 1.2rem;
      color: var(--loading-subtitle-color);
    }

    footer {
      text-align: center;
      padding: 40px 0;
      margin-top: 40px;
      color: var(--secondary-color);
      border-top: 1px solid rgba(0, 0, 0, 0.1);
    }

    .hidden {
      display: none;
    }

    @media (max-width: 768px) {
      h1 {
        font-size: 2.5rem;
      }
      
      .card-container {
        grid-template-columns: 1fr;
      }
    }