* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: sans-serif;
}
ul,
li {
  padding: 0;
  margin: 0;
  list-style: none;
}
a {
  text-decoration: none;
  color: #000;
}

.iconnav i {
  color: #fff;
  font-size: 20px;
  display: none;
}

.topnav {
  background-color: #000;
  position: relative;
}
.topnav ul {
  display: flex;
  justify-content: center;
  align-items: center;
}

.topnav a {
  display: block;
  padding: 10px 20px;
  color: #fff;
}

.topnav a:hover {
  background-color: aqua;
}

@media (max-width: 600px) {
  .topnav ul {
    flex-direction: column;
    justify-content: flex-start;
  }
  .topnav li {
    width: 100%;
    text-align: left;
  }
  .iconnav {
    position: absolute;
    top: 0;
    right: 0;
    display: block;
    padding: 10px;
  }
  .iconnav i {
    display: block;
  }
}