li {
display: inline-block;
font-size: 0;
}
li a {
display:inline-block;
text-align:center;
font: normal 16px Arial;
text-transform: uppercase;
}
a:hover {
font-weight:bold;
}
/* SOLUTION */
/* The pseudo element has the same content and hover style, so it pre-sets the width of the element and visibility: hidden hides the pseudo element from actual view. */
a::before {
display: block;
content: attr(title);
font-weight: bold;
height: 0;
overflow: hidden;
visibility: hidden;
}