header,
nav,
nav ul {
  display: flex;
}
body,
nav ul {
  margin: 0;
  padding: 0;
}
body,
nav ul li a {
  font-family: Poppins, sans-serif;
  color: #fff;
}
header,
nav ul,
nav ul li a:hover::after {
  width: 100%;
}
body {
  background-color: #000;
  overflow-x: hidden;
}
header {
  align-items: center;
  padding: 10px 0;
  background: 0 0;
  z-index: 999;
  position: fixed;
  top: 0;
  justify-content: center;
  transition: background-color 0.8s, backdrop-filter 0.8s;
}
header.background-opaque {
  background-color: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(10px);
}
header .logo,
header nav ul li a {
  opacity: 1;
  transition: none;
}
.header-container {
  display: flex;
  align-items: center;
  width: 100%;
  justify-content: center;
  position: relative;
}
.logo-item {
  margin-right: 5px;
}
.logo {
  width: 50px;
  transition: transform 0.5s;
  vertical-align: -35px;
}
.logo:hover {
  transform: rotate(360deg);
}
.logo-item a::after {
  content: none;
}
nav {
  justify-content: center;
  align-items: center;
}
nav ul {
  list-style-type: none;
  align-items: center;
  justify-content: center;
}
nav ul li {
  margin: 0 15px;
}
nav ul li a {
  text-decoration: none;
  font-size: 16px;
  font-weight: 700;
  padding: 10px 0;
  position: relative;
  transition: 0.3s;
}
nav ul li a::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: 0;
  width: 0;
  height: 1px;
  background-color: #fff;
  transition: width 0.3s;
  transform: translateX(-50%);
}
.ia {
  background: linear-gradient(
    90deg,
    #fff 0,
    #d3d3d3 25%,
    #181818 50%,
    #c7c7c7 75%,
    #292929 100%
  );
  background-size: 300% 300%;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  animation: 5s linear infinite rgbAnimation;
  text-shadow: 0 0 10px rgba(255, 255, 255, 0.4);
}
@keyframes rgbAnimation {
  0%,
  100% {
    background-position: 0 0;
  }
  50% {
    background-position: 100% 100%;
  }
}