:root {
  --nav-height: 0px;
}

.hero-video iframe {
  position: absolute;
  top: 50%;
  left: 50%;
  -webkit-transform: translate(-50%, -50%) scale(1.08);
  transform: translate(-50%, -50%) scale(1.08);
  -webkit-transform-origin: center center;
  transform-origin: center center;
  pointer-events: none;
  -webkit-transition: -webkit-transform 0.15s linear;
  transition: -webkit-transform 0.15s linear;
  transition: transform 0.15s linear;
  transition:
    transform 0.15s linear,
    -webkit-transform 0.15s linear;
}

#hero-video-section {
  min-height: calc(100vh - var(--nav-height));
}

@media (min-aspect-ratio: 16/9) {
  .hero-video iframe {
    width: 100vw;
    height: 56.25vw;
  }
}

@media (max-aspect-ratio: 16/9) {
  .hero-video iframe {
    width: 177.78vh;
    height: 100vh;
  }
}

@media (max-width: 991.98px) {
  .navbar-brand img {
    height: 90px;
  }

  #hero-video-section h1 {
    font-size: calc(1.8rem + 2vw);
  }

  #hero-video-section .lead {
    font-size: 1.1rem;
  }
}

@media (max-width: 575.98px) {
  .navbar-brand img {
    height: 72px;
  }
}

footer a:hover {
  color: var(--bs-secondary);
}

#btn-back-to-top {
  position: fixed;
  bottom: 20px;
  right: 20px;
  z-index: 1050;
  opacity: 0;
  -webkit-transition: opacity 0.3s ease-in-out;
  transition: opacity 0.3s ease-in-out;
}

#btn-back-to-top.show {
  display: block !important;
  opacity: 1;
}

#topicssection .position-relative:hover img {
  opacity: 0.85;
}