*{
  margin:0;
  padding:0;
  box-sizing: border-box;
}
body{
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background: #1e2759;
}
ul{
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
  border-radius: 5px;
  box-shadow: 0 5px 25px rgba(0, 0, 0, .2);
}
ul li{
  list-style: none;
}
ul li a{
  position: relative;
  color: #fff;
  text-decoration: none;
  display: inline-block;
  padding: 10px 15px;
  z-index: 1000;
  backdrop-filter: blur(15px);
}
ul li a ion-icon{
  font-size: 2.5em;
  pointer-events: none;
  opacity: .2;
  transition: .3s;
}
ul li.active a ion-icon{
  opacity: 1;
}
#marker{
  position: absolute;
  top: 0;
  transition: .5s;
  z-index: 1;
}
#marker::before{
  content: '';
  position: absolute;
  top:-10px;
  left: 50%;
  transform: translateX(-50%);
  width: 50px;
  height: 40px;
  border-radius: 15px;
}
ul li:nth-child(1).active ~ #marker::before{
  background: #5da6ff;
  box-shadow: 
  0 0 30px #5da6ff,
  0 0 45px #5da6ff,
  0 0 60px #5da6ff,
  0 0 15px #5da6ff;
}
ul li:nth-child(2).active ~ #marker::before{
  background: #ff0;
  box-shadow: 
  0 0 30px #ff0,
  0 0 45px #ff0,
  0 0 60px #ff0,
  0 0 15px #ff0;
}
ul li:nth-child(3).active ~ #marker::before{
  background: #0f0;
  box-shadow: 
  0 0 30px #0f0,
  0 0 45px #0f0,
  0 0 60px #0f0,
  0 0 15px #0f0;
}
ul li:nth-child(4).active ~ #marker::before{
  background: #f00;
  box-shadow: 
  0 0 30px #f00,
  0 0 45px #f00,
  0 0 60px #f00,
  0 0 15px #f00;
}
ul li:nth-child(5).active ~ #marker::before{
  background: #df2fff;
  box-shadow: 
  0 0 30px #df2fff,
  0 0 45px #df2fff,
  0 0 60px #df2fff,
  0 0 15px #df2fff;
}