Rounded tag shape with CSS

Question

I am trying to create this shape with html/css:

My requirements are:

• body background might change per page, so cannot use alpha masking images
• the background color is transitionable on hover
• all corners of the shape are rounded

With sharp corners you could do it with css triangles, but the rounded ones give me trouble.

What I have so far in HTML:

<ul class="tags">
  <li><a href="#">Lorem</a></li>
  <li><a href="#">Ipsum</a></li>
  <li><a href="#">Longer text in tag</a></li>
  <li><a href="#">Dolor</a></li>
</ul>

In CSS:

.tags {
  list-style: none;
  margin: 0;
  padding: 1em;
}
.tags li {
    display: inline-block;
    margin-right: 2em;
    position: relative;
}
.tags a {
    background: #283c50;
    color: #fff;
    display: block;
    line-height: 1em;
    padding: 0.5em;
    text-decoration: none;

    -webkit-border-radius: 10px 0 0 10px;
    -moz-border-radius: 10px 0 0 10px;
    border-radius: 10px 0 0 10px;

    -webkit-transition: background 200ms ease;
    -moz-transition: background 200ms ease;
    -o-transition: background 200ms ease;
    -ms-transition: background 200ms ease;
    transition: background 200ms ease;
}
.tags a:before {
    background: #283c50;
    content: "";
    height: 1.75em;
    width: 1.75em;
    position: absolute;
    top: 0.1em;
    right: -0.87em;
    z-index: -1;

    -webkit-transform: rotate(40deg);
    -moz-transform: rotate(40deg);
    -o-transform: rotate(40deg);
    -ms-transform: rotate(40deg);
    transform: rotate(40deg);

    -webkit-border-radius: 0.625em;
    -moz-border-radius: 0.625em;
    -o-border-radius: 0.625em;
    -ms-border-radius: 0.625em;
    border-radius: 0.625em;

    -webkit-transition: background 200ms ease;
    -moz-transition: background 200ms ease;
    -o-transition: background 200ms ease;
    -ms-transition: background 200ms ease;
    transition: background 200ms ease;
}
.tags a:hover,
.tags a:hover:before {
    background: #1eaa82;
}

It only looks ok on Chrome. For others, there are either differences in the triangle position or transition occurs at different times for the triangle and the actual tag. See example http://jsfiddle.net/hfjMk/1/

Is this even possible/feasible? Or do I have to discard the transition and use an image for the triangle part?

Answer 1

You could use a rotated pseudo element for this:

div {
  height: 50px;
  width: 150px;
  border-radius: 10px 0 0 10px;
  position: relative;
  background: tomato;
  text-align:center;
  line-height:50px;
}
div:before {
  content: "";
  position: absolute;
  top: -4px;
  right: -41px;
  height: 41px;
  width: 41px;
  transform-origin: top left;
  transform: rotate(45deg);
  background: tomato;
  border-radius: 10px;
}

<div>Text</div>