:root {
      --page-app-primary-color: #FFD700; /* Vàng */
      --page-app-secondary-color: #FFFFFF; /* Trắng */
      --page-app-background-color: #000000; /* Đen */
      --page-app-text-color: #FFFFFF;
      --page-app-heading-color: #FFD700;
      --page-app-button-bg: #FFD700;
      --page-app-button-text: #000000;
      --page-app-border-color: #444444;
    }

    .page-app {
      font-family: 'Arial', sans-serif;
      background-color: var(--page-app-background-color);
      color: var(--page-app-text-color);
      line-height: 1.6;
      padding-bottom: 80px; /* Space for fixed footer */
    }

    .page-app__container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 15px;
    }

    .page-app__hero-section {
      background-color: #1a1a1a;
      text-align: center;
      padding: 10px 0 40px; /* Added padding-top for fixed header */
      position: relative;
      overflow: hidden;
    }

    .page-app__hero-image {
      width: 100%;
      height: auto;
      max-width: 100%;
      display: block;
      margin: 0 auto;
      border-radius: 8px;
    }

    .page-app__hero-content {
      position: relative;
      z-index: 1;
      padding: 20px 15px;
      color: var(--page-app-text-color);
    }

    .page-app__hero-title {
      font-size: 2.5em;
      color: var(--page-app-heading-color);
      margin-bottom: 10px;
      line-height: 1.2;
    }

    .page-app__hero-description {
      font-size: 1.1em;
      margin-bottom: 20px;
      max-width: 800px;
      margin-left: auto;
      margin-right: auto;
    }

    .page-app__button {
      display: inline-block;
      background-color: var(--page-app-button-bg);
      color: var(--page-app-button-text);
      padding: 12px 25px;
      border-radius: 30px;
      text-decoration: none;
      font-weight: bold;
      font-size: 1.05em;
      transition: background-color 0.3s ease, transform 0.2s ease;
      border: none;
      cursor: pointer;
    }

    .page-app__button:hover {
      background-color: #FFC107;
      transform: translateY(-2px);
    }

    .page-app__section {
      padding: 40px 0;
      border-bottom: 1px solid var(--page-app-border-color);
    }

    .page-app__section:last-of-type {
      border-bottom: none;
    }

    .page-app__section-title {
      font-size: 2em;
      color: var(--page-app-heading-color);
      text-align: center;
      margin-bottom: 30px;
    }

    .page-app__features-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
      gap: 30px;
      margin-top: 30px;
    }

    .page-app__feature-item {
      background-color: #1a1a1a;
      padding: 25px;
      border-radius: 10px;
      text-align: center;
      border: 1px solid var(--page-app-border-color);
      transition: transform 0.3s ease;
    }

    .page-app__feature-item:hover {
      transform: translateY(-5px);
    }

    .page-app__feature-icon {
      width: 100px;
      height: auto;
      max-width: 100%;
      margin-bottom: 15px;
      display: block;
      margin-left: auto;
      margin-right: auto;
    }

    .page-app__feature-title {
      font-size: 1.3em;
      color: var(--page-app-primary-color);
      margin-bottom: 10px;
    }

    .page-app__download-steps {
      display: flex;
      flex-direction: column;
      gap: 25px;
      margin-top: 30px;
    }

    .page-app__step-item {
      display: flex;
      align-items: flex-start;
      background-color: #1a1a1a;
      padding: 20px;
      border-radius: 10px;
      border: 1px solid var(--page-app-border-color);
    }

    .page-app__step-number {
      font-size: 1.8em;
      font-weight: bold;
      color: var(--page-app-primary-color);
      margin-right: 15px;
      flex-shrink: 0;
      width: 40px;
      text-align: center;
    }

    .page-app__step-content h3 {
      font-size: 1.2em;
      color: var(--page-app-primary-color);
      margin-top: 0;
      margin-bottom: 5px;
    }

    .page-app__step-content p {
      margin-bottom: 0;
      color: var(--page-app-text-color);
    }

    .page-app__game-categories {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
      gap: 20px;
      margin-top: 30px;
    }

    .page-app__game-item {
      background-color: #1a1a1a;
      padding: 15px;
      border-radius: 10px;
      text-align: center;
      border: 1px solid var(--page-app-border-color);
      transition: transform 0.3s ease;
    }

    .page-app__game-item:hover {
      transform: translateY(-5px);
    }

    .page-app__game-image {
      width: 100px;
      height: auto;
      max-width: 100%;
      margin-bottom: 10px;
      display: block;
      margin-left: auto;
      margin-right: auto;
    }

    .page-app__game-title {
      font-size: 1em;
      color: var(--page-app-primary-color);
      font-weight: bold;
    }

    .page-app__providers-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
      gap: 20px;
      margin-top: 30px;
    }

    .page-app__provider-item {
      background-color: #1a1a1a;
      padding: 15px;
      border-radius: 10px;
      text-align: center;
      border: 1px solid var(--page-app-border-color);
      display: flex;
      align-items: center;
      justify-content: center;
      min-height: 100px;
      transition: transform 0.3s ease;
    }

    .page-app__provider-item:hover {
      transform: scale(1.05);
    }

    .page-app__provider-logo {
      max-width: 100px;
      height: auto;
      max-height: 70px;
      display: block;
    }

    .page-app__faq-list {
      margin-top: 30px;
    }

    .page-app__faq-item {
      background-color: #1a1a1a;
      border: 1px solid var(--page-app-border-color);
      border-radius: 8px;
      margin-bottom: 15px;
      overflow: hidden;
    }

    .page-app__faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 15px 20px;
      cursor: pointer;
      user-select: none;
      background-color: #222222;
      transition: background-color 0.3s ease;
    }

    .page-app__faq-question:hover {
      background-color: #2c2c2c;
    }

    .page-app__faq-question h3 {
      margin: 0;
      font-size: 1.1em;
      color: var(--page-app-primary-color);
      pointer-events: none; /* Prevent h3 from blocking click event */
    }

    .page-app__faq-toggle {
      font-size: 1.5em;
      font-weight: bold;
      color: var(--page-app-primary-color);
      margin-left: 15px;
      transition: transform 0.3s ease;
      pointer-events: none; /* Prevent toggle icon from blocking click event */
    }

    .page-app__faq-item.active .page-app__faq-toggle {
      transform: rotate(45deg); /* Change '+' to 'x' or '-' */
    }

    .page-app__faq-answer {
      max-height: 0;
      overflow: hidden;
      padding: 0 15px;
      opacity: 0;
      transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1), padding 0.4s ease, opacity 0.3s ease;
      color: var(--page-app-text-color);
    }

    .page-app__faq-item.active .page-app__faq-answer {
      max-height: 2000px !important; /* Sufficiently large to contain content */
      padding: 20px 15px !important;
      opacity: 1;
    }

    .page-app__floating-promo {
      position: fixed;
      bottom: 0;
      left: 0;
      width: 100%;
      background-color: #FFD700;
      padding: 10px 15px;
      text-align: center;
      box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.3);
      z-index: 1000;
    }

    .page-app__floating-promo-button {
      background-color: #FF4500; /* Cam */
      color: #FFFFFF;
      padding: 10px 20px;
      border-radius: 25px;
      font-weight: bold;
      font-size: 1.1em;
      border: none;
      cursor: pointer;
      box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
      transition: background-color 0.3s ease;
      width: 100%;
      max-width: 400px;
    }

    .page-app__floating-promo-button:hover {
      background-color: #E03C00;
    }

    /* Responsive adjustments */
    @media (max-width: 768px) {
      .page-app__hero-title {
        font-size: 2em;
      }

      .page-app__hero-description {
        font-size: 1em;
      }

      .page-app__section-title {
        font-size: 1.8em;
      }

      .page-app__features-grid {
        grid-template-columns: 1fr;
      }

      .page-app__download-steps {
        flex-direction: column;
      }

      .page-app__step-item {
        flex-direction: column;
        align-items: center;
        text-align: center;
      }

      .page-app__step-number {
        margin-right: 0;
        margin-bottom: 10px;
      }

      .page-app__game-categories {
        grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
      }

      .page-app__providers-grid {
        grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
      }

      .page-app__faq-question {
        padding: 12px 15px;
      }

      .page-app__faq-question h3 {
        font-size: 1em;
      }

      .page-app__faq-answer {
        padding: 15px 15px !important;
      }

      .page-app__hero-section {
        padding-top: 10px; /* Adjust for mobile header height */
      }

      /* Image responsive optimization for mobile */
      .page-app img {
        max-width: 100% !important;
        height: auto !important;
      }
      .page-app__hero-image {
        width: 100% !important;
        height: auto !important;
      }
      .page-app__feature-icon {
        width: 100% !important;
        height: auto !important;
      }
      .page-app__game-image {
        width: 100% !important;
        height: auto !important;
      }
      .page-app__provider-logo {
        width: 100% !important;
        height: auto !important;
      }
      .page-app__container img,
      .page-app__section img,
      .page-app__hero-section img,
      .page-app__feature-item img,
      .page-app__game-item img,
      .page-app__provider-item img {
        width: 100%;
        max-width: 100%;
        height: auto;
        overflow: hidden;
        box-sizing: border-box;
      }
    }