styles.css

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body,
html {
  border: none;
  width: 100vw;
  height: 100vh;
  background-color: #333639;
  font-family: "Poppins", Poppins, sans-serif;
  color: white;
}

iframe {
  border: none;
  height: 100%;
  width: min(100%, 100vw);
}

ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
}

li {
  padding: 10px;
  text-align: center;
}

li:last-child {
  position: absolute;
  right: 0;
  margin-right: 0.5rem;
}

/* Underline styles */
a {
  text-decoration: none;
  color: inherit;
  display: block;
  position: relative;
  padding: 0.2em 0;
}

/* Fade in */
a::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 0.1em;
  background-color: white;
  opacity: 0;
  transition: opacity 300ms, transform 300ms;
}

a:hover::after,
a:focus::after {
  opacity: 1;
  transform: translate3d(0, 0.2em, 0);
}

@media only screen and (max-width: 600px) {
  body {
    justify-content: center;
    width: auto;
    height: 100vh;
  }
  ul {
    justify-content: center;
  }
  li:last-child {
    position: relative;
    margin-right: 0;
  }
}