html {
  scroll-behavior: smooth;
}
body{
  margin: 0;
}
a {
    color: #031d30;
}

/* ---------- Header ---------- */
header{ 
  background-color:white;
  position: fixed;
  top:0px;
  width: 100%;
  z-index:10;
}

nav{
  width: 100%;
  max-width: 960px;
  height: 90px;
  margin: 0px auto;
  display: flex;
  align-items:center;
}

nav> a {
  text-decoration: none; 
  font-size: 130%;
  font-weight: 400;
  letter-spacing: 1px;
  padding: 30px 25px 0 25px; 
  height: 60px;
}
      
nav> a:hover {
  background-color: #f3f3f3;
}
      
nav> a.active {
  background-color: #048;
  color: #f7fbff;
}
nav a:first-child {flex-grow:1;}

@media(max-width:768px) {
  nav> a {
    padding: 30px 15px 0 15px; 
  }
}
@media(max-width:440px) {
  nav a:not(.active) {display:none;}
  nav a:first-child {display:inline;}
}

/* ---------- top part ---------- */

#title_top {
  width: 100%;
  background-color: #004080;
  box-shadow: 0px 4px 10px black;
  height:5px;
}

/* ---------- Main part ---------- */
main{
  font-size: 16px;
  max-width: 940px;
  margin: auto; 
  margin-top: 120px;
  color:#333;
}

@media(min-width:480px) {
  main{ 
   width: 90%; 
  }
}

main h2, summary{
  color:#004080;
  font-size: 22px;
  font-weight: bold;
}

article > h2:first-child{
  font-size: 30px;
  background-color: #F5FFFF;  
  padding: 10px 0px 10px 10px; 
  border-bottom: solid #D0F0F0;
}

dt {
  float: left; 
  width: 55px;
  text-align: right;
  font-weight: bold;
}

dd {
  margin: 0 0 10px 80px;
}

article{
  box-shadow: 0 0 0.5rem #999;
  border-radius: 15px;  
  width:100%;
}

article >div{
  padding:0px 15px 10px 15px; 
}