How to create slanted tabs with a border in CSS?

Question

I am trying to create angled tabs to sit above a content section, and came across this great example:

HTML:

<div class="tab">
    <div class="arrow"></div>
</div>

CSS:

body
{
    background-color: #666;    
}
.tab
{
    height: 50px;
    width: 150px;
    border-radius: 10px 10px 0px 0px;
    background-color: #FFF;
    position: relative;
}

.arrow
{
  border-color: transparent transparent #FFF #FFF;
  border-style: solid;
  border-width: 23px 23px 23px 23px;
  height:0;
  width:0;
  position:absolute;
  bottom:0px;
  right:-43px;
}

http://jsfiddle.net/P3P3Z/2/

However, I would like to set a different 2px border colour to this shape, and unfortunately this method doesn't work as it uses the border to create the right hand side of the shape.

Any ideas on how I could mod it?

Solution

You can try this approach: jsFiddle

Instead of using the borders to create the slanted effect, I'm using an :after pseudo element to create it. This allows me to set borders around it. Then I'm using a :before pseudo element to hide the borders which I don't want to see. The recurring 2px in the CSS is derived from the border width value.

CSS

.tab:before {
    height: 50px;
    width: 10px;
    display: block;
    content:" ";
    background-color: #FFF;
    position: absolute;
    right: -2px;
    top: -2px;
    border-top: 2px solid blue;
    border-bottom: 2px solid blue;
}
.tab {
    height: 50px;
    width: 150px;
    border-radius: 10px 10px 0px 0px;
    background-color: #FFF;
    position: relative;
    border: 2px solid blue;
}
.tab:after {
    display: block;
    content:" ";
    width: 100px;
    height: 50px;
    top: -2px;
    background-color: #FFF;
    position: absolute;
    right: -29px;
    transform:skewX(45deg);
    -ms-transform:skewX(45deg);
    -webkit-transform:skewX(45deg);
    border: 2px solid blue;
    z-index: -1;
}

Comments

[Andrea Ligios]

+1. This is similar to my technique used here: stackoverflow.com/a/13273672/1654265 where i use after and before as two triangles overlapped and a bit shifted one from each other...

[alias51]

Thanks, I've modified your approach for some advanced styling, here: jsfiddle.net/robmc/ZvEyx/4 I want to try and achieve the styled top right curve corner on the tab; I dont think you need the tab:before for this, but I cant see a way to get rid of the blue curve on the parent. Any ideas?

[Mathijs Flietstra]

Just turn off the border-radius on the top right corner of the tab and move the :after pseudo element a bit more to the right (increase its negative right margin): jsfiddle.net/ZvEyx/6