Pseudo-elements and padding - html

Question

I want to get some practice with pseudo elements in combination with transitions and animations. But I have one little problem.
Have a look at this:
HTML:
<nav id="navBar" class="clearfix">
Test
</nav>
CSS:
.clearfix:after {
content: ".";
clear: both;
display: block;
visibility: hidden;
height: 0px;
}
#navBar {
width: 100%;
padding: 30px;
border-top: 1px solid #808080;
border-bottom: 1px solid #808080;
box-sizing: border-box;
}
#navBar a {
text-decoration: none;
display: inline-block;
}
a.nav {
padding: 10px;
background-color: #7492b6;
color: #fff;
float: left;
font-weight: bold;
font-size: 1em;
min-width: 150px;
text-align: center;
}
a.nav::before {
content: "";
display: block;
position: relative;
top: 0;
left: 0;
width: 100%;
height: 3px;
background-color: #fff;
padding: 0;
}
a.nav::after {
content: "";
display: block;
position: relative;
top: 0;
left: 0;
width: 100%;
height: 3px;
background-color: #fff;
padding: 0;
}
http://codepen.io/anon/pen/rVbeLa
the two red lines are my pseudo elements. But I want them to have width 100% but it's not working in combination with the padding.
It should look like this but then I have no padding :/
http://codepen.io/anon/pen/RPOaRj
I have tested it on Firefox 39 and Chrome 43, both on OSX yosemite. Result is the same on both.
Any Idea how this problem could be solved?
Cheers

Answer 1

You can fix that by doing this.
Add position:relative; to the <a>:
#navBar a {
text-decoration: none;
display: inline-block;
position:relative;
}
Then, change your :before and :after to position:absolute; and change their position from top and bottom:
.navGroup1 a.nav::before {
content: "";
display: block;
position: absolute;
top: 10px;
left: 0;
width:100%;
height: 3px;
background-color: red;
}
.navGroup1 a.nav::after {
content: "";
display: block;
position: absolute;
bottom:10px;
left: 0;
width: 100%;
height: 3px;
background-color: red;
}
Updated Codepen