html {
   box-sizing: border-box;
}

*, *:before, *:after {
   box-sizing: inherit;
}

body {
   min-height: 100vh;
   margin: 0;
   /* Important! */
   font-family: sans-serif;
   background: linear-gradient(45deg, hsla(340, 100%, 55%, 1) 0%, hsla(340, 100%, 55%, 0) 70%), linear-gradient(135deg, hsla(225, 95%, 50%, 1) 10%, hsla(225, 95%, 50%, 0) 80%), linear-gradient(225deg, hsla(140, 90%, 50%, 1) 10%, hsla(140, 90%, 50%, 0) 80%), linear-gradient(315deg, hsla(35, 95%, 55%, 1) 100%, hsla(35, 95%, 55%, 0) 70%);
}

.wrapper {
   margin: 0 auto;
   max-width: 500px;
   font-size: 20px;
   line-height: 2;
   position: relative;
}

a {
   text-decoration: none;
   color: black;
   background: rgba(0, 0, 0, 0.05);
   border-radius: 20px
}

.highlight {
   transition: all 0.25s;
   border-bottom: 2px solid white;
   position: absolute;
   top: 0;
   background: white;
   left: 0;
   z-index: -1;
   border-radius: 20px;
   display: block;
   box-shadow: 0 0 10px rgba(0, 0, 0, 0.2)
}

.menu {
   padding: 0;
   display: flex;
   list-style: none;
   justify-content: center;
   margin: 100px 0;
}

.menu a {
   display: inline-block;
   padding: 5px;
   margin: 0 20px;
   color: black;
}