#background {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: -1;
  background-color: #333
}
#background .item {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  width: 100%;
  height: 100vh;
}
#background .item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: 30% 50%;
}
.fade {
  transition: opacity ease 1s;
  opacity: 0;
}
.fade.show {
  opacity: 1;
}
* {
  font-family: "Roboto";
}
body {
  margin: 0;
  background-color: #333;
  color: #fff;
}
nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  padding: 20px;
  z-index: 100;
  background-color: rgba(0, 0, 0, 0.1);
}
nav div {
  display: flex;
  justify-content: center;
  align-items: center;
  margin: 0 auto;
  max-width: 900px
}
nav ul li {
  list-style: none;
  display: flex;
  margin: 0 15px;
}
nav ul li img {
  max-height: 150px;
  width: 100%;
  max-width: 130px
}
.filter_invert {
  filter: invert(1);
}
#welcome {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}
#welcome .content {
  font-size: 40px;
  text-align: center;
  text-transform: uppercase;
  font-weight: bold;
  margin: 0 auto;
  max-width: 900px
}
#welcome .content svg {
  position: absolute;
  animation: MoveUpDown .8s ease-in-out infinite;
  bottom: 30px;
  left: 50%;
  transform: translateX(-50%);
  width: 30px;
  height: 30px
}
@keyframes MoveUpDown {
  0%,
  100% {
    bottom: 15px;
  }
  50% {
    bottom: 30px;
  }
}
#about {
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: #fff;
  color: #333;
  min-height: 100vh;
}
#about .content {
  font-size: 18px;
  margin: 0 auto;
  max-width: 1120px;
  padding: 20px;
}
#main .content {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-gap: 20px;
  padding: 20px;
  max-width: 1200px;
  margin: 0 auto;
}
@media (max-width: 900px) {
  #main .content {
    grid-template-columns: repeat(2, 1fr);
  }
}
@media (max-width: 600px) {
  #main .content {
    grid-template-columns: repeat(1, 1fr);
  }
}
#main {
  padding-top: 150px;
  background-color: rgba(255, 255, 255, 0.9);
}
#main .content .pdf {
  margin: 20px;
  display: flex;
  flex-direction: column;
  text-decoration: none;
  position: relative;
  height: 500px;
  overflow: hidden;
  color: #fff;
}
#main .pdf img {
  width: 100%;
  height: 100%;
  object-fit: contain;
}
#main .content .pdf.portrait img {
  object-fit: contain;
}
#main .content .pdf .ctx {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 20px;
  background-color: rgba(0, 0, 0, 0.5);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity ease 0.5s;
}
#main .content .pdf:hover .ctx {
  opacity: 1;
}