CSS

nav items moving when hover

<ul>
    <li><a href="#" title="height">height</a></li>
    <li><a href="#" title="icon">icon</a></li>
    <li><a href="#" title="left">left</a></li>
    <li><a href="#" title="letter-spacing">letter-spacing</a></li>
    <li><a href="#" title="line-height">line-height</a></li>
</ul>
 Run code snippet

nav items moving when hover

a, li {
  color: black;
  text-decoration: none;
  font: 18px sans-serif;
  letter-spacing: 0.03em;
}
li {
  display: inline-block;
  margin-right: 20px;
  color: gray;
  font-size: 0.7em;
}
.bold-x1 a.hover:hover,
.bold-x1 a:not(.hover) {
  text-shadow: 0 0 .01px black;
}
.bold-x2 a.hover:hover,
.bold-x2 a:not(.hover){
  text-shadow: 0 0 .01px black, 0 0 .01px black;
}
.bold-x3 a.hover:hover,
.bold-x3 a:not(.hover){
  text-shadow: 0 0 .01px black, 0 0 .01px black, 0 0 .01px black;
}
.bold-native a.hover:hover,
.bold-native a:not(.hover){
  font-weight: bold;
}

.bold-native li:nth-child(4),
.bold-native li:nth-child(5){
 margin-left: -6px;
 letter-spacing: 0.01em;
}