/*Navigation styling */#navigation {display:table;/* Webkit Fix */margin-left:310px;text-align:center; /* center list items*/ margin-top:-40px;list-style:none;background:#586949;font-family: 'PT Sans Narrow', sans-serif;text-transform: uppercase;font-size: 20px;}#navigation ul {padding: 0;list-style: none;}#navigation li {list-style: none;padding-left:30px;height: 28px;padding-top:3px;text-align: center;background-color: #586949;display:-moz-inline-box; /* FF2 and K-Meleon */display:inline-block;word-spacing:0; /* reset from parent ul*/}#navigation li a {color: #fff;text-decoration: none;display:block;margin-top:-1px;}/*hide drop down links*/#navigation li ul {display:none;position: absolute;}#navigation li a:hover {border-bottom: 3px solid #ffffff;}/*drop down styling*/#navigation li:hover ul {display:block;margin-left:-27px;margin-bottom:5px;padding-bottom:10px;float:left;text-align:left;z-index:1;width:190px;background-color: #586949;}
.button { background: orange; -webkit-box-sizing: border-box; -moz-box-sizing: border-box; box-sizing: border-box; padding: 10px;}.button:hover { border: 3px solid black; padding: 7px;}
http://mbmitservices.co.uk/charity/index.html
This works:
Just remove the border width from the original padding. It might work also without the box-sizing, but I haven't tested that.