html, body {
      margin: 0;
      padding: 0;
      font-family: 'Segoe UI', sans-serif;
      background: #f9f9f9;
      color: #333;
      overflow-x: hidden;
    }

    .intro-overlay {
      position: fixed;
      top: 0;
      left: 0;
      width: 100vw;
      height: 100vh;
      background: black;
      display: flex;
      justify-content: center;
      align-items: center;
      z-index: 9999;
      animation: hideOverlay 2.5s forwards;
    }

    .intro-overlay h1 {
      color: white;
      font-size: 3rem;
      opacity: 0;
      transform: scale(0.8);
      animation: titleSequence 2.5s ease forwards;
    }

    @keyframes titleSequence {
      0%   { opacity: 0; transform: scale(0.8); }
      50%  { opacity: 1; transform: scale(1.2); }
      100% { opacity: 1; transform: scale(1); }
    }

    @keyframes hideOverlay {
      0% { opacity: 1; }
      90% { opacity: 1; }
      100% {
        opacity: 0;
        visibility: hidden;
        display: none;
      }
    }

    .fade-in {
      opacity: 0;
      transform: translateY(20px);
      animation: fadeIn 1s ease forwards;
    }

    @keyframes fadeIn {
      to {
        opacity: 1;
        transform: translateY(0);
      }
    }

    .main-content {
      display: none;
    }

    .container {
      max-width: 960px;
      margin: auto;
      padding: 2rem;
    }

    header {
      background: #ffffff;
      border-bottom: 1px solid #ddd;
      padding: 1rem 2rem;
      display: flex;
      justify-content: space-between;
      align-items: center;
      position: sticky;
      top: 0;
      z-index: 100;
    }

    header h1 {
      margin: 0;
      font-size: 1.5rem;
    }

    nav {
      display: flex;
      gap: 1rem;
    }

    nav a {
      text-decoration: none;
      color: #4a90e2;
      font-weight: bold;
      position: relative;
      padding: 0.5rem 1rem;
    }

    nav a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0%;
      height: 2px;
      background: #4a90e2;
      transition: width 0.3s ease;
    }

    nav a:hover::after {
      width: 100%;
    }

    .hero {
      background: linear-gradient(135deg, #e0f7fa, #f9f9f9);
      padding: 4rem 2rem;
      text-align: center;
    }

    .hero h2 {
      font-size: 2.5rem;
      margin-bottom: 1rem;
    }

    .hero p {
      font-size: 1.2rem;
      color: #555;
      max-width: 700px;
      margin: auto;
    }

    section h3, section h4 {
      margin-top: 2rem;
      color: #222;
    }

    section p {
      line-height: 1.6;
      margin-top: 0.5rem;
    }

    ul {
      padding-left: 1.2rem;
    }

    ul li {
      margin-bottom: 0.5rem;
    }

    footer {
      text-align: center;
      padding: 2rem;
      font-size: 0.9rem;
      color: #888;
      border-top: 1px solid #ddd;
      background: #fff;
    }

    .social-icons {
      margin-top: 1rem;
      display: flex;
      justify-content: center;
      gap: 1rem;
    }

    .social-icons a {
      text-decoration: none;
      font-size: 1.2rem;
      color: #4a90e2;
    }

    /* Desktop nav visible only on wider screens */
header {
  display: flex;
}

.mobile-nav {
  display: none;
}

/* Mobile nav styles */
@media (max-width: 768px) {
  header {
    display: none;
  }

  .mobile-nav {
    display: block;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: #fff;
    z-index: 1000;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
  }

  .mobile-nav-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
  }

  .mobile-nav-header h1 {
    font-size: 1.2rem;
    margin: 0;
  }

  .hamburger {
    font-size: 1.5rem;
    background: none;
    border: none;
    cursor: pointer;
    color: #4a90e2;
  }

  .mobile-nav-links {
    display: none;
    flex-direction: column;
    padding: 0 1rem 1rem 1rem;
  }

  .mobile-nav-links a {
    text-decoration: none;
    color: #4a90e2;
    font-weight: bold;
    padding: 0.5rem 0;
    border-bottom: 1px solid #eee;
  }

  .hero {
    padding-top: 10rem;
  }
}

/* Mobile nav hidden by default */
.mobile-nav {
  display: none;
}

/* Mobile nav styles */
@media (max-width: 768px) {
  header {
    display: none;
  }

  .mobile-nav {
    display: block;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: #fff;
    z-index: 1000;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
  }

  .mobile-nav-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
  }

  .mobile-nav-header h1 {
    font-size: 1.2rem;
    margin: 0;
  }

  .hamburger {
    font-size: 1.5rem;
    background: none;
    border: none;
    cursor: pointer;
    color: #4a90e2;
  }

  .mobile-nav-links {
    display: flex;
    flex-direction: column;
    overflow: hidden;
    max-height: 0;
    transition: max-height 0.4s ease;
    padding: 0 1rem;
  }

  .mobile-nav-links a {
    text-decoration: none;
    color: #4a90e2;
    font-weight: bold;
    padding: 0.75rem 0;
    border-bottom: 1px solid #eee;
  }

  .mobile-nav-links.open {
    max-height: 500px; /* Enough to show all links */
  }

  .hero {
    padding-top: 10rem;
  }
}

.ad-modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.6);
  display: none;
  justify-content: center;
  align-items: center;
  z-index: 1000;
}

.ad-grid {
  background: #fff;
  padding: 2rem;
  border-radius: 10px;
  max-width: 1000px;
  width: 95%;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
  position: relative;
  box-shadow: 0 8px 24px rgba(0,0,0,0.2);
  animation: adPopIn 0.3s ease-out;
}

.ad-card {
  background: #f9f9f9;
  border-radius: 6px;
  padding: 1rem;
  text-align: center;
  box-shadow: 0 2px 6px rgba(0,0,0,0.05);
}

.ad-card img {
  width: 100%;
  max-width: 120px;
  margin-bottom: 0.5rem;
  border-radius: 4px;
}

.ad-card h4 {
  font-size: 1rem;
  margin-bottom: 0.5rem;
  color: #333;
}

.ad-card a {
  display: inline-block;
  padding: 0.4rem 0.8rem;
  background: #0078D4;
  color: white;
  text-decoration: none;
  border-radius: 4px;
  font-size: 0.85rem;
  font-weight: bold;
}

.ad-close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  font-size: 1.5rem;
  background: none;
  border: none;
  cursor: pointer;
  color: #333;
}

@keyframes adPopIn {
  from {
    transform: scale(0.9);
    opacity: 0;
  }
  to {
    transform: scale(1);
    opacity: 1;
  }
}

.ad-heading {
  position: fixed;
  top: 1%;
  left: 50%;
  transform: translateX(-50%) translateY(-20px);
  background: #fff;
  padding: 0.5rem 1rem;
  border-radius: 6px;
  font-size: 1.5rem;
  font-weight: 600;
  color: #222;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
  opacity: 0;
  transition: opacity 0.4s ease, transform 0.4s ease;
  z-index: 1001; /* above modal backdrop */
}

.ad-heading.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}



.main-content {
  position: relative; /* creates stacking context */
  overflow: hidden;   /* optional: prevents scroll during intro */
}

.intro-overlay {
  position: absolute; /* relative to .main-content */
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 999;
  background: #000;
  animation: fadeOut 2.5s ease forwards;
  pointer-events: none;
}

@media (max-width: 768px) {
  .ad-grid {
    grid-template-columns: repeat(2, 1fr); /* fewer columns */
    padding: 1rem;
    gap: 1rem;
    width: 90%;
    max-width: 100%;
    border-radius: 6px;
  }

  .ad-card img {
    max-width: 100px;
  }

  .ad-heading {
    font-size: 1.2rem;
    padding: 0.5rem;
    top: 1rem;
  }

  .ad-modal-content {
    width: 95%;
    max-width: 320px;
    padding: 1rem;
  }

  .ad-close {
    top: 0.25rem;
    right: 0.5rem;
    font-size: 1.2rem;
  }

    .ad-modal {
    align-items: flex-start;
    padding-top: 4rem;
    overflow-y: auto;
  }

  .ad-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
    max-height: calc(100vh - 8rem);
    overflow-y: auto;
    padding: 1rem;
  }

  .ad-card {
    padding: 0.75rem;
  }

  .ad-card img {
    max-width: 80px;
  }

  .intro-overlay {
  height: 100vh;
  width: 100vw;
  padding: 0 1rem;
  box-sizing: border-box;
  text-align: center;
}

.intro-overlay h1 {
  font-size: 2rem;
  word-break: break-word;
  max-width: 90%;
  margin: 0 auto;
}
}