* {
  margin: 0;
  padding: 0;
}
.header {
  background-color: blue;
  display: flex;
  align-items: center;
  margin: 0px;
  padding: 20px;
}
.logo-site {
  margin-left: 20px;
  font-weight: bold;
  font-size: 1.3em;
}
ul {
  list-style: none;
  display: flex;
  width: 100vw;
  justify-content: center;
}
li {
  margin-left: 50px;
  font-size: 1.1em;
}
button {
  padding: 7px 20px 7px 20px;

  font-weight: bold;
  cursor: pointer;
}
a {
  text-decoration: none;
  color: #000;
  margin-right: 20px;
}
button:hover {
  background-color: yellow;
}
button:active {
  background-color: green;
}