Weird CSS behavior - Diagonal border - Why is the border edge not straight?

Question

I want to add a white gap between menu elements but Im encountering a weird problem. See this jfiddle: http://jsfiddle.net/ERYat/1/

Here is the CSS code:

/* a styling */
ul#menu-menu-services a {
    display: block;
    font-size: 20px;
    color: #000;
    text-decoration: none;
    padding: 5px;
    border-bottom: 2px solid #fff;
    border-left-style: solid;
    border-left-width: 3px;
    border-left-color: #000;
}
/* li fix */
ul#menu-menu-services li {
    margin: 0;
    padding: 0;
    border: none;

}

/* Sub Menu */
ul#menu-menu-services li ul.sub-menu {
    display: block;
    margin-left: 0px;
}

ul#menu-menu-services li ul.sub-menu li a {
    padding-left: 15px;
    font-size: 14px;
}

I can't figure out why is the border diagonal on the left. Anyone knows?

Answer 1

Borders come together like this:

||
||______
|/______

You should use margin-bottom instead of border-bottom fiddle:

ul#menu-menu-services a {
display: block;
font-family: 'Droid Sans', arial, serif;
font-size: 20px;
color: #000;
text-decoration: none;
padding: 5px;
margin-bottom: 2px;
border-left-style: solid;
border-left-width: 3px;
border-left-color: #000;
}

And if you need a white line, consider using :after:

ul#menu-menu-services a { position: relative; }
ul#menu-menu-services a:after {
    content: '';
    width: 100%;
    position: absolute;
    height: 2px;
    background: #fff;
    left: 0;
    bottom: -2px;
}