* {
  padding: 0;
  margin: 0;
  white-space: nowrap; /* 禁止换行 */
}

h2,
h3,
.unable {
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

.index_bk {
  background-color: antiquewhite;
  color: aliceblue;
  height: 100%;
  background-image: url("images/index_bk.png");
  background-repeat: no-repeat;

  background-position: center;
  background-size: cover;

  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.index_bk h2 {
  font-size: 60px;
}

.index_bk p {
  color: antiquewhite;
  margin: 20px 0;
}

.index_bk a {
  color: aliceblue;
  text-decoration: none;
  border: 1px solid #acacac;
  padding: 10px 20px;
  border-radius: 5px;
}

header {
  background-color: black;
  height: 80px;
  width: 100%;
}

header h1,
header h2,
header p,
header li {
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

header h1 {
  color: aliceblue;
  position: absolute;
  left: 50px;
  top: 0;
  line-height: 80px;
}

header ul {
  padding-left: 1100px;
  right: 5%;
  top: 0;
  line-height: 80px;
}

header li {
  display: inline;
  margin-right: 40px;
}

header a {
  color: aliceblue;
  text-decoration: none;
}

header .home:hover {
  text-decoration: none;
}

header a:hover {
  text-decoration: underline;
}

@media (min-width: 100px) {
  header ul {
    text-align: right;
  }
}