Question

In this JSFiddle, the last .tab class doesn’t get the correct border-radius effect (top right rounded corner).

I think I have my logic correct in saying :last-child selects the last .tab of .tabbed in this case.

What am I doing wrong?

CSS:

body {
    background: black;
    color: white;
    padding: 5px; }

.tabbed {
    height: 550px;
}

.tabbed .tab {
    padding: 6px 14px;
    background: rgba(255,255,255,0.25);
    border: 1px solid rgba(255,255,255,0.4);
    border-radius: 0px;
    border-left-width: 0;
    float: left;
}

.tabbed .tab:first-child {
    border-radius: 3px 0 0 0;
    border-left-width: 1px;
}

.tabbed .tab:last-child {
    border-radius: 0 3px 0 0;
}

HTML:

<ul class='tabbed'>
    <li class='tab'>Menu 1</li>
    <li class='tab'>Menu 2</li>
    <li class='tab'>Menu 3</li>
    <li class='tab'>Menu 4</li>
    <li class='tab'>Menu 5</li>
    <li> <br/><br/> </li>
    <li class='dummy'>Content 1</li>
    <li class='dummy'>Content 2</li>
    <li class='dummy'>Content 3</li>
    <li class='dummy'>Content 4</li>
    <li class='dummy'>Content 5</li>
</ul>

Answer 1

In a comment, you state: “It needs to be on the same ul parent. Or another ul, below the last li on the first ul.” If that is so, then do this:

<ul class='tabbed'>
    <li class='tab'>Menu 1</li>
    <li class='tab'>Menu 2</li>
    <li class='tab'>Menu 3</li>
    <li class='tab'>Menu 4</li>
    <li class='tab'>Menu 5</li>
    <li>
    <ul>
    <li class='dummy'>Content 1</li>
    <li class='dummy'>Content 2</li>
    <li class='dummy'>Content 3</li>
    <li class='dummy'>Content 4</li>
    <li class='dummy'>Content 5</li>
    </ul>
    </li>
</ul>

Then this css (with modern browsers):

.tabbed {
height: 550px; }

.tabbed .tab {
padding: 6px 14px;
background: rgba(255,255,255,0.25);
border: 1px solid rgba(255,255,255,0.4);
border-radius: 0px;
border-left-width: 0;
float: left; }

.tabbed .tab:first-child {
border-radius: 3px 0 0 0;
border-left-width: 1px; }

.tabbed .tab:nth-last-child(2) {
border-radius: 0 3px 0 0; }

.tabbed li:last-child {
   clear: left;
}

See this fiddle.