index.css

* {
  margin: 0px;
}
/*header*/
#header-background {
  position: absolute;
  z-index: -1;
  height: 38px;
  left: 0px;
  right: 0px;
  top: 0px;
  background: #222222;
}
h1 {
  font-family: "DM Serif Display", serif;
  font-style: normal;
  font-weight: normal;
  font-size: 24px;
  color: aqua;
  text-align: center;
  align-content: center;
  margin: 0px;
  height: 38px;
}
h4 {
  font-size: 18px;
  position: fixed;
  bottom: 0;
}
li {
  display: inline-flex;
  list-style-type: none;
  text-align: center;
}
.nav-menu {
  display: flex;
  justify-content: center;
  height: 60px;
  background: coral;
  margin: 0px;
}
.nav-menu-bar {
  font-family: "Roboto Slab", serif;
  font-weight: bold;
  font-size: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 245px;
}
.nav-menu a:link,
a:visited {
  color: white;
  text-decoration: none;
}

.nav-menu a:hover,
a:active {
  background-color: red;
}