body{
  width: 100%;
  height: 100%;
  margin: 0;
  padding-top: 60px; 
  background-color: #EEEEEE;
}
.wrap{
  max-width: 1200px;
  margin-left: auto;
  margin-right: auto;
  background-color: #FAFAFA;
}
.Header{
  background: #aaa url(header_bg.png) center no-repeat;
  position: relative;
  height: 300px;
  color: #333;
  background-size: cover;
  left: 0;
  pointer-events: none;
  top: 0;
  width: 100%;
}
.Header-wrap{
  width: 100%;
  height: 100%;
  background-color: rgba(31, 31, 31, 1);
  opacity: 0.7;
  display: block;
}
.Header_title{
  width: 100%;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 80px;
  text-align: center;
  color: white;
  font-weight: bold;
}
.session{
  /* display: flex; */
  max-width: 1200px;
  margin: 20px auto;
  overflow-wrap: break-word;
  font-size: 15px;
  padding:10px;
}
.center{
  text-align: center;
}
.left{
  text-align: left;
}
.session_title{
  font-size: 25px;
  font-weight: bold;
  list-style-type: disc;
  margin-left: 20px;
}
li {
  margin: 5px 0px 0px 20px;
}
table{
  border-spacing: 15px 5px;
}
th{
  width: 85px;
  text-align-last: justify;
}
a:link, a:visited, a:hover, a:active {
  color: blue;
}
footer{
  max-width: 1200px;
  text-align: right;
  margin-right: auto;
  margin-left: auto;
}
hr{
  width: 90%;
}
.indent{
  margin-left: 40px;
}
header {
  position: fixed;
  width: 100%; 
  height: 60px; 
  background: #CCC; 
  padding: 20px 60px; 
  box-sizing: border-box;
  top: 0; 
  left: 0; 
  display: flex; 
  align-items: center; 
  z-index: 1;

  display: flex; 
  justify-content:space-between;
}

header .nav .menu {
  display: flex; 
}

header .nav .menu li {
  list-style: none; 
  margin-left: 40px;
}

header .nav .menu li a{
 color: black;
 font-weight:bold;
 text-decoration: none;
}

.bt_login{
  width: 200px;
  font-size: 20px;
  margin: 10px;
  background-color: orange;
  border-radius: 7px;
}
.bt_sign{
  width: 200px;
  font-size: 20px;
  font-size: 20px;
  margin: 10px;
  border-radius: 7px;
}