html, body {
      margin: 0;
      padding: 0;
      height: 100%;
      overflow-x: hidden;
    }
    .responsive-wrapper-desktop {
      width: 100vw;
      min-height: 100vh;
      overflow-y: auto;
      position: relative;
    }
    .rules-background {
      background: url('https://ctkm.catalan.vn/wp-content/themes/ctkm-theme/images/tl_d.png') no-repeat top center;
      background-size: 100% auto;
      aspect-ratio: 1920 / 4000;
      width: 100vw;
      position: relative;
    }
    @keyframes pulse {
      0% {
        transform: scale(1);
        opacity: 1;
      }
      50% {
        transform: scale(1.08);
        opacity: 0.85;
      }
      100% {
        transform: scale(1);
        opacity: 1;
      }
    }
    .btn-tgn {
      position: absolute;
      top: 41%;
      left: 50%;
      transform: translate(-50%, -50%);
      z-index: 10;
    }
    .btn-tgn img {
      width: 20vw;
      max-width: 300px;
      height: auto;
      animation: pulse 2s infinite;
    }
    .button-group-fixed {
      position: absolute;
      top: 79%;
      left: 50%;
      transform: translateX(-50%);
      display: flex;
      justify-content: center;
      gap: 2vw;
      flex-wrap: wrap;
      width: 100%;
      box-sizing: border-box;
    }
    .button-group-fixed img {
      width: 20vw;
      max-width: 300px;
      height: auto;
      animation: pulse 2s infinite;
    }
    .back-btn {
      position: fixed;
      top: 20px;
      right: 20px;
      z-index: 999;
    }
    .back-btn img {
      max-width: 40px;
      height: auto;
    }