Tabs border with triangle with CSS

Question

I am trying to represent my HTML/CSS tab like on the picture.

I have already tried lots of things with border-radius without any success. Do you have any tracks so that I can reproduce my tabs like the picture only with CSS?

Answer 1

In order to make the same borders (also inside the triangles) as in the image, you can use pseudo elements and transform rotate :

DEMO

output :

HTML :

<div>Critiques</div>
<div>Messages sur le forum</div>
<div>Actualités</div>

CSS :

div{
    border-top:1px solid #ccc;
    border-bottom:1px solid #ccc;
    padding-right:12px;
    line-height:50px;
    float:left;
    width:200px;
    position:relative;
    z-index:0;
    text-align:center;
}

div:after,div:before{
    content:'';
    position:absolute;
    width:10px;
    height:10px;
    background:#fff;
    z-index:999;

    -ms-transform: rotate(45deg);
    -webkit-transform: rotate(45deg);
    transform: rotate(45deg);
}

div:before{
    border-right:1px solid #ccc;
    border-bottom:1px solid #ccc;
    top:0; left:-12px;

     -ms-transform-origin:100% 0;
    -webkit-transform-origin:100% 0;
    transform-origin:100% 0;
}

div:after{
    border-left:1px solid #ccc;
    border-top:1px solid #ccc;
    bottom:0;
    right:4px;

     -ms-transform-origin:0 100%;
    -webkit-transform-origin:0 100%;
    transform-origin:0 100%;
}
div:first-child:before, div:last-child:after{
    display:none;
}

Answer 2

You could that with css only but with an empty span (If you would like to have half triangles in the edges):

HTML

<ul>
    <li><span></span>one</li>
    <li><span></span>two</li>
    <li><span></span>three</li>
</ul>

CSS

    ul {
        font-size: 0;
    }

    li {
        background: red;
        display: inline-block;
        padding: 30px;
        font-size: 15px;
        position: relative;
    }

    span {
        position: absolute;
        top: 0;
        bottom: 0;
        left: 0;
        right: 0;
    }

    li:after {
        width: 0;
        height: 0;
        border-top: 10px solid white;
        border-left: 10px solid transparent;
        position: absolute;
        right: 0;
        top: 0;
        content: "";
    }

    li:before {
        width: 0;
        height: 0;
        border-top: 10px solid white;
        border-right: 10px solid transparent;
        position: absolute;
        left: 0;
        top: 0;
        content: "";
    }

    span:before {
        width: 0;
        height: 0;
        border-bottom: 10px solid white;
        border-right: 10px solid transparent;
        position: absolute;
        left: 0;
        bottom: 0;
        content: "";
    }

    span:after {
        width: 0;
        height: 0;
        border-bottom: 10px solid white;
        border-left: 10px solid transparent;
        position: absolute;
        right: 0;
        bottom: 0;
        content: "";
    }

An example: http://jsfiddle.net/fC9Fs/