php - When hovering over <nav> link, website randomly changes the hover background size -


while working on website, have decided incorporate php play around with. figure i'm paying in hosting (sort of), might use it. problem having when hover on link in nav bar have made, hover "decoration" using changes hover background height. problem is, on every page not time. seems random. reason seems doing more on page have seen on others. haven't made changes others make them stop nor changes make start more.

the site in question http://www.journeytomyoasis.com

since can't post images yet, here link screenshot

error http://journeytomyoasis.com/images/common/hover_error.png

code in top of page

<?php $page_title = "about | journey oasis"; ?>  <div id="fb-root"></div> <script>(function(d, s, id) {     var js, fjs = d.getelementsbytagname(s)[0];     if (d.getelementbyid(id)) return;     js = d.createelement(s); js.id = id;     js.src = "//connect.facebook.net/en_us/all.js#xfbml=1&appid=15681725508";     fjs.parentnode.insertbefore(js, fjs); }(document, 'script', 'facebook-jssdk'));</script>  <?php include("includes/header.php");?> <?php include("includes/navigation.php");?> 

code in navigation.php

<!-- begin navigation --> <nav>     <div id="nav_container">         <div id="menu">              <a href="http://www.journeytomyoasis.com/about.php">about</a>               <a href="http://www.journeytomyoasis.com/blog">blog</a>              <a href="http://www.journeytomyoasis.com/portfolio.php">portfolio</a>             <a href="http://www.journeytomyoasis.com/blog/journey/">journey</a>             <a href="http://www.journeytomyoasis.com">home</a>          </div>     </div> </nav> <!--end navigation--> 

at top of page included facebook code using know there in case might think it. have poured on code lot cant see error. fact same php file used on pages , every page has had issue @ least once not confuses me.

i have tested on firefox , ie 10

thank all.

have @ around line 110 of structure.css:

#menu a:hover {     background: #c2d4ec;     height: 41;     color: white; } 

you're explicitly setting height of menu items 41px (browsers assume pixels if don't specify unit, though technically it's not allowed) on hover. remove , won't change size.