* {
  margin: 0;
  padding: 0;
}
header {
  height: 200px;
}
header img {
  width: 100%;
  height: 100%;
}
footer {
  color: #fff;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: 30px;
  box-sizing: border-box;
  height: 200px;
  background-color: #b91c1a;
}
footer .desc {
  font-size: 12px;
}
.nav {
  width: 90%;
  margin: 0 auto;
  height: 50px;
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background-color: #b91c1a;
}
.nav .nav-item {
  cursor: pointer;
  height: 100%;
  width: 19%;
  line-height: 50px;
  text-align: center;
}
.nav .nav-item:hover {
  color: #b91c1a;
  background-color: yellow;
}