HTML5 / CSS3 Circle with Partial Border

Yes, it is possible - see this:

demo

.circle {
  position: relative;
  margin: 7em auto;
  width: 16em;
  height: 16em;
  border-radius: 50%;
  background: lightblue;
}

.arc {
  overflow: hidden;
  position: absolute;
  /* make sure top & left values are - the width of the border */
  /* the bottom right corner is the centre of the parent circle */
  top: -1em;
  right: 50%;
  bottom: 50%;
  left: -1em;
  /* the transform origin is the bottom right corner */
  transform-origin: 100% 100%;
  /* rotate by any angle */
  /* the skew angle is 90deg - the angle you want for the arc */
  transform: rotate(45deg) skewX(30deg);
}

.arc:before {
  box-sizing: border-box;
  display: block;
  border: solid 1em navy;
  width: 200%;
  height: 200%;
  border-radius: 50%;
  transform: skewX(-30deg);
  content: '';
}
<div class='circle'>
  <div class='arc'></div>
</div>

It's possible.

  • Draw two circles using border-radius one on top of another.
  • Make one or more arc of both circles transparent by changing border-color.
  • Use transform to rotate the second circle and you will have the arc of the size you need.

Here is the demo: http://jsfiddle.net/kJXwZ/2/

.wrapper {
  position: relative;
  margin: 20px;
}

.arc {
  position: absolute;
  top: 0;
  left: 0;
  width: 100px;
  height: 100px;
  border-radius: 100%;
  border: 1px solid;
}

.arc_start {
  border-color: transparent red red red;
  -webkit-transform: rotate(45deg);
  -moz-transform: rotate(45deg);
  -ms-transform: rotate(45deg);
  -o-transform: rotate(45deg);
  transform: rotate(45deg);
}

.arc_end {
  border-color: red red red transparent;
  -webkit-transform: rotate(75deg);
  -moz-transform: rotate(75deg);
  -ms-transform: rotate(75deg);
  -o-transform: rotate(75deg);
  transform: rotate(75deg);
}
<div class="wrapper">
  <div class="arc arc_start"></div>
  <div class="arc arc_end"></div>
</div>