This animation(css3) not working on Firefox

Question

This animation http://jsfiddle.net/ts9AG/ is not working on (the latest version of) Firefox. But works in Firefox 26. I don't know why it's not working. It uses only border width & background color.

.loader.pulse {
  width: 40px;
  height: 40px;
  border: 20px solid red;
  box-sizing: border-box;
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
  border-radius: 50%;
  -moz-border-radius: 50%;
  -webkit-border-radius: 50%;
  animation: Loader 1.3s linear 0 infinite;
  -moz-animation: Loader 1.3s linear 0 infinite;
  -webkit-animation: Loader 1.3s linear 0 infinite;
  -o-animation: Loader 1.3s linear 0 infinite;
}

@-webkit-keyframes Loader {
  0% {
    background: #ddd;
    border: 20px solid red;
  }
  49.9% {
    background: #ddd;
    border: 0px solid red;
  }
  50% {
    background: red;
    border: 20px solid #ddd;
  }
  100%{
    background: red;
    border: 0px solid #ddd;
  }
}

@-moz-keyframes Loader {
  0% {
    background: #ddd;
    border: 20px solid red;
  }
  49.9% {
    background: #ddd;
    border: 0px solid red;
  }
  50% {
    background: red;
    border: 20px solid #ddd;
  }
  100%{
    background: red;
    border: 0px solid #ddd;
  }
}

@keyframes Loader {
  0% {
    background: #ddd;
    border: 20px solid red;
  }
  49.9% {
    background: #ddd;
    border: 0px solid red;
  }
  50% {
    background: red;
    border: 20px solid #ddd;
  }
  100%{
    background: red;
    border: 0px solid #ddd;
  }
}

Answer 1

Firefox 26 seem to interpret the 0 in animation: Loader 1.3s linear 0 infinite as a time value even though it shouldn't. If you change to 0s it should work. http://jsfiddle.net/ts9AG/1/

-moz-animation: Loader 1.3s linear 0s infinite;
-webkit-animation: Loader 1.3s linear 0s infinite;
-o-animation: Loader 1.3s linear 0s infinite;
animation: Loader 1.3s linear 0s infinite;