h1 Hover or Click on the links
ul.bar
  - for (var c = 0; c < 4; c++)
    li
      - var link = "#";
      - var title = "Click me";
      - var name = "Link";
      a(href=link title=title) #{name}
      
View Compiled
@import url("https://fonts.googleapis.com/css?family=Montserrat");

$width: 1em;
$bg: #201c29;
$color: #ab49de;

body {
  margin: 0;
  display: flex;
  height: 100vh;
  flex-direction: row;
  justify-content: space-around;
  align-items: center;
  font: 62.5% "Montserrat", sans-serif;
  background-color: $bg;
  background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACMAAAAjCAQAAAC00HvSAAAAqUlEQVR4AaXTIa7EMBBEwfrSAAODwAUfGBiY5P7H26XDIqXfAUrpseI520fcAf+itgEqgW4TMugoCKA2J4DanAQ6CgKozYmg44IMuhVk0FaQQceEDLoNyKBtQAZtExKozQkot7Dv37e42rqoaUk6Koe21ngJLYMManN6034xJzz2UnqvvugY+fNvIIOWIoW24aHnG20V/yJtTgAtAyKozQmgpURdLp+nOT9tfAyifaRWFwAAAABJRU5ErkJggg==);
}

h1 {
  transform: rotate(180deg);
  text-transform: uppercase;
  text-align: center;
  font-size: 2rem;
  writing-mode: vertical-rl;
  color: $color;
  background-image: linear-gradient(
    -90deg,
    $color,
    darken($color, 50%)
  );
  -webkit-background-clip: text;
	-webkit-text-fill-color: transparent;
  user-select: none;
}

.bar {
  margin: 0;
  padding: $width;
  display: flex;
  min-width: 380px;
  height: 100px;
  justify-content: space-around;
  align-items: center;

  li {
    position: relative;
    list-style: none;
    border-radius: $width;

    &::before,
    &::after {
      position: absolute;
      left: 50%;
      transform: translateX(-50%);
      z-index: -1;
      content: "";
      width: 0%;
      height: 2px;
      background-color: darken($color, 10%);
      // transition: all 0.6s cubic-bezier(1, -1, 0.65, -1.05);   
      transition: all 0.5s cubic-bezier(0.4, -1, 0.2, -1);
    }

    &:before {
      top: 0;
      border-top-right-radius: $width / 2;
      border-top-left-radius: $width / 2;
    }
    &::after {
      bottom: 0;
      border-bottom-right-radius: $width / 2;
      border-bottom-left-radius: $width / 2;
    }

    &:hover {
      &::before,
      &::after {
        width: 25%;
        height: 3px;
      }
    }

    a {
      text-decoration: none;
      text-transform: uppercase;
      display: block;
      padding: $width / 2 ($width * 2);
      font-size: 1rem;
      font-weight: 700;
      color: lighten($color, 20%);
    }

    &.active {
      border-color: darken($color, 40%);

      &::before,
      &::after {
        width: 100%;
        height: 50%;
      }
    }
  }
}
let bar = Array.from(document.querySelectorAll("li"));

bar.forEach(function(it) {
  it.onclick = function() {
    bar.forEach(function(el) {
      el.classList.remove("active");
    });
    this.classList.toggle("active");
  };
});

External CSS

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External JavaScript

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