:root {
  --underline-height: .5em;
  --transition-duration: .5s;
  --underline-color: #ffffff;
}

nav {
  position: relative;
  margin-top:20px;
  white-space: nowrap;
  background: white;
  padding: var(--underline-height) 0;
  box-shadow: 0 1em 2em rgba(0, 0, 0, 0.08);
}

.underline {
  display: block;
  position: absolute;
  z-index: 0;
  bottom: 0;
  left: 0;
  height: var(--underline-height);
  width: 16.6%;
  background: #f7a600;
  pointer-events: none;
  /* mix-blend-mode: multiply; */
  -webkit-transition: -webkit-transform var(--transition-duration) ease-in-out;
  transition: -webkit-transform var(--transition-duration) ease-in-out;
  transition: transform var(--transition-duration) ease-in-out;
  transition: transform var(--transition-duration) ease-in-out, -webkit-transform var(--transition-duration) ease-in-out;
}

/* .underline:nth-child(1) {
  background: yellow;
  -webkit-transition: calc(var(--transition-duration) * .8);
  transition: calc(var(--transition-duration) * .8);
}

.underline:nth-child(2) {
  background: cyan;
  -webkit-transition: calc(var(--transition-duration) * 1.2);
  transition: calc(var(--transition-duration) * 1.2);
}

.underline:nth-child(3) {
  background: magenta;
} */

nav a {
  display: inline-block;
  z-index: 10;
  width: 16%;
  padding: 1em 0;
  text-align: center;
  cursor: pointer;
  color: #000;
}


nav a:hover{
  display: inline-block;
  z-index: 10;
  width: 20%;
  padding: 1em 0;
  text-align: center;
  cursor: pointer;
  color: #000;
  text-decoration: none;
}

nav.black .underline {
  background: #ffffff;
  border-radius: .25em;
  height: calc(var(--underline-height) / 2);
  /* mix-blend-mode: initial; */
}
/* 
nav.full {
  font-weight: bold;
  background: rgb(182, 126, 4);;
  color: white;
}

nav.full .underline {
  height: 100%;
  background: gold;
} */

nav.retro .underline {
  border-radius: 100% 100% 0 0;
  color: #ffffff;
}

/* nav.retro .underline:nth-child(1) {
  background: gold;
}

nav.retro .underline:nth-child(2) {
  background: dodgerblue;
} */

nav.retro .underline:nth-child(3) {
  background: #f7a600;
}