* {
  font-family: "PingFang SC", "Noto Sans CJK SC", "Source Han Sans CN", "Microsoft YahHei", Arial, Helvetica, sans-serif;
  margin: 0;
  padding: 0;
  border: 0;
  box-sizing: border-box;
}

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
}

a {
  text-decoration: none;
  color: inherit;
}

header {
  position: absolute;
  width: 100%;
  z-index: 10;
}

nav {
  width: 100%;
  padding: 5px 12px;
}

nav > li {
  display: inline-block;
  padding: 8px 8px;
  cursor: pointer;
  color: #666;
}

nav > li::after{
  content: '';
  display: block;
  width: 100%;
  height: 2px;
  position: relative;
  bottom: -2px;
  background: #666;
  transition: all 0.3s ease-in-out;
  transform: scale3d(0,1,1);
  transform-origin: 50% 0;
}

nav > li:hover::after {
  transform: scale3d(1,1,1);
}

main {
  width: 100%;
  height: 100%;
  z-index: 0;
  background-color: #ddd;
}

section#background {
  position: absolute;
}

h1 {
  font-weight: 200;
  font-size: 96px;
  position: relative;
  margin: 0 auto;
  top: 25%;
  text-align: center;
  vertical-align: middle;
}

h3 {
  color: #666;
  font-weight: 200;
  font-size: 42px;
  position: relative;
  margin: 0 auto;
  top: 25%;
  text-align: center;
  vertical-align: middle;
}

section#sub {
  position: relative;
  margin: 0 auto;
  top: 30%;
  text-align: center;
  vertical-align: middle;
}

section#sub input {
  width: 20em;
  max-width: 95%;
  padding: 5px 18px;
  border-radius: 8px;
  font-weight: 200;
  font-size: 26px;
  text-align: center;
  opacity: 0.6;
  outline: none;
  transition: opacity 1s ease-in-out;
}

section#sub > p {
  opacity: 0;
  margin: 5px auto;
  font-weight: 400;
  font-size: 18px;
  color: grey;
  transition: opacity .6s ease-in-out;
}

section#sub > a {
  display: inline-block;
  width: 120px;
  height: 38px;
  padding: 10px 20px;
  font-size: 18px;
  line-height: 1;
  border: 1px solid black;
  border-radius: 10px;
  transition: all .3s ease-in;
}

section#sub > a:hover {
  background-color: rgba(255, 255, 255, 0.5);
}

section#sub > a:first-of-type {
  margin-right: 70px;
}

footer {
  position: absolute;
  width: 100%;
  bottom: 0;
  padding: 5px 0;
  font-family: Arial, Helvetica, sans-serif;
  font-size: 14px;
  text-align: center;
}