It's because your font-style:italic
takes extra space.
You can add some fixed width
to the li
.
#menu #nav {
font-family: Segoe UI, Arial, sans-serif;
font-size: 14px;
color: #000;
list-style: none;
}
#menu #nav li {
display: inline-block;
padding: 0px 10px 0px 10px;
width: 50px;
}
#menu #nav li a {
font-family: Segoe UI, Arial, sans-serif;
font-size: 14px;
color: #000;
text-decoration: none;
}
#menu #nav li a:hover {
color: #0a813c;
font-style: italic;
}
<div id="menu">
<ul id="nav">
<li><a href="index.php">Pagrindinis</a></li>
<li><a href="#">Taisyklės</a></li>
<li><a href="#">Pamokos</a></li>
<li><a href="#">Kontaktai</a></li>
<li><a href="#">Facebook</a></li>
</ul>
</div>