body{
  margin: 1em;
  padding: .2em;
  padding-left: 1em;
  padding-right: 1em;
  background: rgba(255,255,255,0.7);
  border-radius: 2%;
  
}
html{
 background-image: url(https://previews.123rf.com/images/eyematrix/eyematrix1401/eyematrix140100013/25471335-periodic-table-of-the-elements-background-illustration.jpg); 
}
section#top{
  background-image: url(https://ak.picdn.net/shutterstock/videos/14759662/thumb/1.jpg);
}
#top-bar{
  background: rgba(255,255,255,0.3);
  font-size: 2em;
  padding-left: .5em;
  padding-right: .5em;
}
#nav{
  position: relative;
  display: inline;
  float: left;
}

#icon, #nav-links{
  font-size: 0.5em;
}

#nav-links{
  background: rgba(100,200,255,0.7);
  font-size: .5em;
  display: none;
  position: absolute;
  height: auto;
  width:11em;
  z-index: 1;
  line-height: 2em;
  border-radius: 12px;
}

#links {
  padding: 0.1em 1em 0.1em 1em;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: space-between;
}

#nav:hover #nav-links{
  display:block;
}

#title{
  text-align: center;
}

a.tab{
  text-decoration: none;
  color: white;
}

a.tab:hover, a.tab:active{
  color: blue;
  text-decoration: underline overline;
}

#top-bar{
  margin-top: none;
  padding-top: 1px;
  text-align:center;
  justify-content:space-between;
  border-bottom: 5px double silver;
}

#table{
  text-align: center;
  margin: 5px;
  max-width:100vw;
  overflow: hidden;
  background: rgba(255,100,200,0.2);
  padding: 1em;
  border-radius: 10%;
  
}

#table figcaption{
  position: center;
}

#table img{
  width:90vw;
  border-radius: 15px;
}