Solution Time
Ok this thread is pretty quiet so I’ll announce the solutions now.
Thanks to all that took part and well done as you all solved it.
As this quiz was hot on the heels of the last one it was obvious that you would need some pseudo content to place the extra round corners as required. However, it wasn’t that straight forward because although you could place the corners easily you couldn’t match the background colours.
The trick was to place another pseudo element underneath the corner that held a background colour to match the body. You all sussed this out pretty quickly and the rest was just fine tuning and positioning.
I had correct entries from Hueij, Eric Watson, Yurikolovsky and Remon (ScallioXtx).
Well done to all and the winner this time will be Hueij simply because it was the first entry received and I was fed up with having too many ties 
Well done Hueij 
Solutions:
This is my original solution which slightly differs to most of the others as I placed the background in one go all the way along the top while others did it on individual elements.
I also ran into an Opera bug when using background-clip as opera let the whole background bleed into the corners when in fact it should have had the opposite effect. (background clip is used on round corners [URL=“http://forrst.com/posts/CSS_Fix_for_Safari_background_bleed_with_round_c-B1x”]to stop the issue shown here.)
(Also note in my solution I have added in the vendor extensions for border-radius in case you want to use it for some older browsers.)
Paul:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<style type="text/css">
body {
padding:20px;
background:#ccc;
}
h2 {
margin:0;
padding:10px;
color:#fff;
}
p {
margin:0 0 1em;
color:#fff;
}
.wrap {
width:760px;
margin:auto;
}
.tab {
margin:0;
padding:0 0 0 10px;
list-style:none;
width:750px;
margin:auto;
position:relative;
float:left;
}
.tab li {
float:left;
margin:0 20px -1px;
position:relative;
z-index:1;
}
.tab li a {
float:left;
padding:5px 20px;
background:#000;
color:#fff;
font-weight:bold;
text-decoration:none;
border:1px solid #000;
border-bottom:none;
-webkit-border-top-left-radius: 10px;
-webkit-border-top-right-radius: 10px;
-moz-border-radius-topleft: 10px;
-moz-border-radius-topright: 10px;
border-top-left-radius: 10px;
border-top-right-radius: 10px;
-webkit-background-clip:padding-box;
-moz-background-clip:padding-box;
/*background-clip:padding-box; buggy in opera 11*/
position:relative;
z-index:3;
}
.tab li.current a, .tab li a:hover {
border-bottom:1px solid red;
position:relative;
z-index:3;
padding:5px 20px 4px;
background:red;
}
.tabbox {
clear:both;
border:1px solid #000;
width:740px;
margin:auto;
background:#f00;
z-index:99;
padding:10px;
-webkit-border-radius: 10px;
-moz-border-radius: 10px;
border-radius: 10px;
-webkit-box-shadow: 5px 4px 4px #0f0d0f;
-moz-box-shadow: 5px 4px 4px #0f0d0f;
box-shadow: 5px 4px 4px #0f0d0f;
}
.tab li:before,.tab li:after {
content:" ";
display:block;
position:absolute;
bottom:0;
left:-20px;
width:20px;
height:20px;
background:#ccc;
border:1px solid #000;
border-top:none;
border-left:none;
z-index:100;
}
.tab li:before{
-webkit-border-bottom-right-radius: 10px;
-moz-border-radius-bottomright: 10px;
border-bottom-right-radius: 10px;
}
.tab li:after {
left:auto;
right:-20px;
-webkit-border-bottom-left-radius: 10px;
-moz-border-radius-bottomleft: 10px;
border-bottom-left-radius: 10px;
border-left:1px solid #000;
border-right:none;
}
.tab a:after,.tab a:before {
content:" ";
display:block;
position:absolute;
z-index:99;
bottom:0;
left:-19px;
width:20px;
height:20px;
background:#000;
}
.tab a:before {
left:auto;
right:-20px;
}
.tab li.current a:after, .tab li a:hover:after, .tab li.current a:before, .tab li a:hover:before {
background:red;
bottom:-1px
}
</style>
</head>
<body>
<div class="wrap">
<ul class="tab">
<li class="current"><a href="#">Tab 1</a></li>
<li><a href="#">Tab 1</a></li>
<li><a href="#">Tab 2</a></li>
<li><a href="#">Tab 3</a></li>
<li><a href="#">Tab 4</a></li>
<li><a href="#">Tab 5</a></li>
</ul>
<div class="tabbox">
<h2>Tab Box</h2>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Duis pellentesque mauris pellentesque justo congue in faucibus justo faucibus. Nunc odio sapien, vehicula eget interdum quis, euismod dignissim magna. Morbi condimentum massa sit amet nisl fringilla quis laoreet sapien porttitor. Aenean adipiscing rutrum accumsan. Cras ipsum ligula, pretium sit amet fermentum et, viverra quis quam. Suspendisse sed lacus augue, a sagittis metus. Nunc pulvinar, purus a semper consequat, enim orci viverra dui, at iaculis quam odio sit amet eros. Aliquam eleifend ipsum et libero sollicitudin dictum eu et ipsum. Phasellus venenatis semper felis, vitae pretium enim fermentum lacinia. Nulla a erat tortor, et fermentum nisi. Suspendisse potenti. Ut pellentesque lorem ut metus convallis viverra. Nam sagittis, mauris sit amet tempor viverra, orci odio condimentum mi, eu semper metus odio vel augue. Nunc diam quam, cursus quis mollis a, rutrum euismod nisl. </p>
</div>
</div>
</body>
</html>
Hueij:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<style type="text/css">
body {
padding:20px;
background:#ccc;
}
h2 {
margin:0;
padding:10px;
color:#fff;
}
p {
margin:0 0 1em;
color:#fff;
}
.wrap {
width:760px;
margin:auto;
}
.tab {
margin:0;
padding:0 0 0 10px;
list-style:none;
width:750px;
margin:auto;
}
.tab li {
float:left;
margin:0 20px -1px;
position:relative;
z-index:1;
}
.tab li:before, .tab li:after {
content: "";
position:absolute;
width:12px;
height:12px;
bottom:0;
background:#000;
z-index:2;
}
.tab li.current:before, .tab li.current:after, .tab li:hover:before, .tab li:hover:after {
background:#FF0000;
}
.tab li:before {
left:-11px;
}
.tab li:after {
right:-11px;
}
.tab li a {
position:relative;
float:left;
padding:5px 20px;
background:#000;
color:#fff;
font-weight:bold;
text-decoration:none;
border:1px solid #000;
border-bottom:none;
border-top-left-radius: 12px;
border-top-right-radius: 12px;
}
.tab li a:before, .tab li a:after {
content:"";
position:absolute;
width:12px;
height:12px;
bottom:0;
background:#ccc;
border-bottom:1px solid #000;
z-index:3;
}
.tab li.current a:before, .tab li.current a:after, .tab li a:hover:before, .tab li a:hover:after {
bottom:-1px;
}
.tab li a:before {
border-right:1px solid #000;
left:-13px;
border-bottom-right-radius: 12px;
}
.tab li a:after {
border-left:1px solid #000;
right:-13px;
border-bottom-left-radius: 12px;
}
.tab li.current a, .tab li a:hover {
border-bottom:1px solid red;
padding:5px 20px 4px;
background:red;
}
.tabbox {
clear:both;
border:1px solid #000;
width:740px;
margin:auto;
background:#f00;
padding:10px;
border-radius: 12px;
box-shadow:6px 6px 6px rgba(0, 0, 0, 0.8);
}
</style>
</head>
<body>
<div class="wrap">
<ul class="tab">
<li class="current"><a href="#">Tab 1</a></li>
<li><a href="#">Tab 1</a></li>
<li><a href="#">Tab 2</a></li>
<li><a href="#">Tab 3</a></li>
<li><a href="#">Tab 4</a></li>
<li><a href="#">Tab 5</a></li>
</ul>
<div class="tabbox">
<h2>Tab Box</h2>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Duis pellentesque mauris pellentesque justo congue in faucibus justo faucibus. Nunc odio sapien, vehicula eget interdum quis, euismod dignissim magna. Morbi condimentum massa sit amet nisl fringilla quis laoreet sapien porttitor. Aenean adipiscing rutrum accumsan. Cras ipsum ligula, pretium sit amet fermentum et, viverra quis quam. Suspendisse sed lacus augue, a sagittis metus. Nunc pulvinar, purus a semper consequat, enim orci viverra dui, at iaculis quam odio sit amet eros. Aliquam eleifend ipsum et libero sollicitudin dictum eu et ipsum. Phasellus venenatis semper felis, vitae pretium enim fermentum lacinia. Nulla a erat tortor, et fermentum nisi. Suspendisse potenti. Ut pellentesque lorem ut metus convallis viverra. Nam sagittis, mauris sit amet tempor viverra, orci odio condimentum mi, eu semper metus odio vel augue. Nunc diam quam, cursus quis mollis a, rutrum euismod nisl. </p>
</div>
</div>
</body>
</html>
Eric Watson:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<style type="text/css">
body {
padding:20px;
background:#ccc;
}
h2 {
margin:0;
padding:10px;
color:#fff;
}
p {
margin:0 0 1em;
color:#fff;
}
.wrap {
width:760px;
margin:auto;
}
.tab {
margin:0;
padding:0 0 0 10px;
list-style:none;
width:750px;
margin:auto;
}
.tab li {
float:left;
margin:0 20px -1px;
position:relative;
z-index:1;
}
.tab li a {
float:left;
padding:5px 20px;
background:#000;
color:#fff;
font-weight:bold;
text-decoration:none;
border:1px solid #000;
border-bottom:none;
-webkit-border-top-left-radius: 8px;
-webkit-border-top-right-radius: 8px;
-moz-border-radius-topleft: 8px;
-moz-border-radius-topright: 8px;
border-top-left-radius: 8px;
border-top-right-radius: 8px;
}
.tab li.current a, .tab li a:hover {
border-bottom:1px solid red;
padding:5px 20px 4px;
background:red;
}
.tabbox {
clear:both;
border:1px solid #000;
width:740px;
margin:auto;
background:#f00;
padding:10px;
-webkit-border-radius: 8px;
-moz-border-radius: 8px;
border-radius: 8px;
-moz-box-shadow:5px 5px 5px #111;
-webkit-box-shadow:5px 5px 5px #111;
box-shadow:5px 5px 5px #111;
}
.tab li:before {
content:"";
position:absolute;
z-index:2;
bottom:0;
left:-10px;
height:10px;
width:10px;
border-right:1px solid #000;
border-bottom:1px solid #000;
-webkit-border-bottom-right-radius:8px;
-moz-border-radius-bottomright:8px;
border-bottom-right-radius:8px;
background:#ccc;
}
.tab a:before {
content:"";
position:absolute;
bottom:0px;
left:-10px;
height:10px;
width:11px;
background:#000;
z-index:1;
}
.tab li:after {
content:"";
position:absolute;
z-index:2;
bottom:0;
right:-10px;
height:10px;
width:10px;
border-left:1px solid #000;
border-bottom:1px solid #000;
-webkit-border-bottom-left-radius:8px;
-moz-border-radius-bottomleft:8px;
border-bottom-left-radius:8px;
background:#ccc;
}
.tab a:after {
content:"";
position:absolute;
bottom:0px;
right:-10px;
height:10px;
width:11px;
background:#000;
z-index:1;
}
.tab li.current a:after, .tab li.current a:before, .tab li a:hover:before, .tab li a:hover:after {
background:red;
}
</style>
</head>
<body>
<!-- http://www.visibilityinherit.com/projects/test38.html -->
<div class="wrap">
<ul class="tab">
<li class="current"><a href="#">Tab 1</a></li>
<li><a href="#">Tab 1</a></li>
<li><a href="#">Tab 2</a></li>
<li><a href="#">Tab 3</a></li>
<li><a href="#">Tab 4</a></li>
<li><a href="#">Tab 5</a></li>
</ul>
<div class="tabbox">
<h2>Tab Box</h2>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Duis pellentesque mauris pellentesque justo congue in faucibus justo faucibus. Nunc odio sapien, vehicula eget interdum quis, euismod dignissim magna. Morbi condimentum massa sit amet nisl fringilla quis laoreet sapien porttitor. Aenean adipiscing rutrum accumsan. Cras ipsum ligula, pretium sit amet fermentum et, viverra quis quam. Suspendisse sed lacus augue, a sagittis metus. Nunc pulvinar, purus a semper consequat, enim orci viverra dui, at iaculis quam odio sit amet eros. Aliquam eleifend ipsum et libero sollicitudin dictum eu et ipsum. Phasellus venenatis semper felis, vitae pretium enim fermentum lacinia. Nulla a erat tortor, et fermentum nisi. Suspendisse potenti. Ut pellentesque lorem ut metus convallis viverra. Nam sagittis, mauris sit amet tempor viverra, orci odio condimentum mi, eu semper metus odio vel augue. Nunc diam quam, cursus quis mollis a, rutrum euismod nisl. </p>
</div>
</div>
</body>
</html>
Yurikolovsky:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<style type="text/css">
body {
padding:20px;
background:#ccc;
}
h2 {
margin:0;
padding:10px;
color:#fff;
}
p {
margin:0 0 1em;
color:#fff;
}
.wrap {
width:760px;
margin:auto;
}
.tab {
margin:0;
padding:0 0 0 10px;
list-style:none;
width:750px;
margin:auto;
}
.tab li {
float:left;
margin:0 20px -1px;
position:relative;
z-index:1;
}
.tab li a {
float:left;
padding:5px 20px;
background:#000;
color:#fff;
font-weight:bold;
text-decoration:none;
border:1px solid #000;
border-bottom:none;
}
.tab li.current a, .tab li a:hover {
border-bottom:1px solid red;
padding:5px 20px 4px;
background:red;
}
.tabbox {
clear:both;
border:1px solid #000;
width:740px;
margin:auto;
background:#f00;
padding:10px;
}
/*CSS added by me*/
.tab li a {
-webkit-border-top-left-radius: 10px;
-webkit-border-top-right-radius: 10px;
-moz-border-radius-topleft: 10px;
-moz-border-radius-topright: 10px;
border-top-left-radius: 10px;
border-top-right-radius: 10px;
}
.tab li:before,
.tab li:after,
.tab a:before,
.tab a:after {
background:#000;
height:11px;
width:11px;
display:block;
content:"";
position:absolute;
bottom:0;
}
.tab .current a:before,
.tab .current a:after,
.tab a:hover:before,
.tab a:hover:after {
background:red;
}
.tab a:before {
left:-10px;
}
.tab a:after {
right:-10px;
}
.tab li:before,
.tab li:after {
background:#ccc;/*heheheheee*/
z-index:2;
border:solid #000 1px;
border-top:0;
}
.tab li:before {
-webkit-border-bottom-right-radius: 10px;
-moz-border-radius-bottomright: 10px;
border-bottom-right-radius: 10px;
left:-11px;
border-left:0;
}
.tab li:after {
-webkit-border-bottom-left-radius: 10px;
-moz-border-radius-bottomleft: 10px;
border-bottom-left-radius: 10px;
right:-11px;
border-right:0;
}
</style>
</head>
<body>
<div class="wrap">
<ul class="tab">
<li class="current"><a href="#">Tab 1</a></li>
<li><a href="#">Tab 1</a></li>
<li><a href="#">Tab 2</a></li>
<li><a href="#">Tab 3</a></li>
<li><a href="#">Tab 4</a></li>
<li><a href="#">Tab 5</a></li>
</ul>
<div class="tabbox">
<h2>Tab Box</h2>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Duis pellentesque mauris pellentesque justo congue in faucibus justo faucibus. Nunc odio sapien, vehicula eget interdum quis, euismod dignissim magna. Morbi condimentum massa sit amet nisl fringilla quis laoreet sapien porttitor. Aenean adipiscing rutrum accumsan. Cras ipsum ligula, pretium sit amet fermentum et, viverra quis quam. Suspendisse sed lacus augue, a sagittis metus. Nunc pulvinar, purus a semper consequat, enim orci viverra dui, at iaculis quam odio sit amet eros. Aliquam eleifend ipsum et libero sollicitudin dictum eu et ipsum. Phasellus venenatis semper felis, vitae pretium enim fermentum lacinia. Nulla a erat tortor, et fermentum nisi. Suspendisse potenti. Ut pellentesque lorem ut metus convallis viverra. Nam sagittis, mauris sit amet tempor viverra, orci odio condimentum mi, eu semper metus odio vel augue. Nunc diam quam, cursus quis mollis a, rutrum euismod nisl. </p>
</div>
</div>
</body>
</html>
Remon:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<style type="text/css">
body {
padding:20px;
background:#ccc;
}
h2 {
margin:0;
padding:10px;
color:#fff;
}
p {
margin:0 0 1em;
color:#fff;
}
.wrap {
width:760px;
margin:auto;
}
.tab {
margin:0;
padding:0 0 0 10px;
list-style:none;
width:750px;
margin:auto;
}
.tab li {
float:left;
margin:0 20px -1px;
position:relative;
z-index:1;
}
.tab li a {
float:left;
padding:5px 20px;
background:#000;
color:#fff;
font-weight:bold;
text-decoration:none;
border:1px solid #000;
border-bottom:none;
border-top-left-radius: 10px;
border-top-right-radius: 10px;
}
.tab li:before,
.tab li:after {
content: '';
position: absolute;
bottom: 0px;
width: 10px;
height: 10px;
background: #ccc;
border: 1px solid;
z-index: 2;
}
.tab li:after {
right: -11px;
border-color: transparent transparent #000 #000;
-webkit-border-bottom-left-radius: 10px;
-moz-border-radius-bottomleft: 10px;
border-bottom-left-radius: 10px;
}
.tab li:before {
left: -11px;
border-color: transparent #000 #000 transparent;
-webkit-border-bottom-right-radius: 10px;
-moz-border-radius-bottomright: 10px;
border-bottom-right-radius: 10px;
}
.tab li a:before,
.tab li a:after {
content: '';
position: absolute;
display: block;
bottom: 0px;
width: 10px;
height: 10px;
background: black;
z-index: 1;
}
.tab li a:before {
left: -9px;
}
.tab li a:after {
right: -9px;
}
.tab li.current a:before,
.tab li.current a:after,
.tab li a:hover:before,
.tab li a:hover:after {
background: red;
}
.tab li.current a,
.tab li a:hover {
border-bottom:1px solid red;
padding:5px 20px 4px;
background:red;
}
.tabbox {
clear:both;
border:1px solid #000;
width:740px;
margin:auto;
background:#f00;
padding:10px;
}
</style>
</head>
<body>
<div class="wrap">
<ul class="tab">
<li class="current"><a href="#">Tab 1</a></li>
<li><a href="#">Tab 1</a></li>
<li><a href="#">Tab 2</a></li>
<li><a href="#">Tab 3</a></li>
<li><a href="#">Tab 4</a></li>
<li><a href="#">Tab 5</a></li>
</ul>
<div class="tabbox">
<h2>Tab Box</h2>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Duis pellentesque mauris pellentesque justo congue in faucibus justo faucibus. Nunc odio sapien, vehicula eget interdum quis, euismod dignissim magna. Morbi condimentum massa sit amet nisl fringilla quis laoreet sapien porttitor. Aenean adipiscing rutrum accumsan. Cras ipsum ligula, pretium sit amet fermentum et, viverra quis quam. Suspendisse sed lacus augue, a sagittis metus. Nunc pulvinar, purus a semper consequat, enim orci viverra dui, at iaculis quam odio sit amet eros. Aliquam eleifend ipsum et libero sollicitudin dictum eu et ipsum. Phasellus venenatis semper felis, vitae pretium enim fermentum lacinia. Nulla a erat tortor, et fermentum nisi. Suspendisse potenti. Ut pellentesque lorem ut metus convallis viverra. Nam sagittis, mauris sit amet tempor viverra, orci odio condimentum mi, eu semper metus odio vel augue. Nunc diam quam, cursus quis mollis a, rutrum euismod nisl. </p>
</div>
</div>
</body>
</html>
Once again thans and congratulations to all those that took part 
I’ll let you have a short break before I post another quiz so that you can all recover a bit.