css animated icon resize

问题

how you use $ in css

[http://codepen.io/jlong/pen/KBhDf][1]

in the above mentioned link on the 3rd line $heartbeat-size: 10px; I wanted to know how to use this element in the style sheet.

回答1:

To answer your question, here is the processed CSS result of the scss in your pen:

@-webkit-keyframes heartbeat {
  0% {
    -moz-transform: rotate(45deg) scale(1);
    -ms-transform: rotate(45deg) scale(1);
    -webkit-transform: rotate(45deg) scale(1);
    transform: rotate(45deg) scale(1);
  }
  14% {
    -moz-transform: rotate(45deg) scale(1.3);
    -ms-transform: rotate(45deg) scale(1.3);
    -webkit-transform: rotate(45deg) scale(1.3);
    transform: rotate(45deg) scale(1.3);
  }
  28% {
    -moz-transform: rotate(45deg) scale(1);
    -ms-transform: rotate(45deg) scale(1);
    -webkit-transform: rotate(45deg) scale(1);
    transform: rotate(45deg) scale(1);
  }
  42% {
    -moz-transform: rotate(45deg) scale(1.3);
    -ms-transform: rotate(45deg) scale(1.3);
    -webkit-transform: rotate(45deg) scale(1.3);
    transform: rotate(45deg) scale(1.3);
  }
  70% {
    -moz-transform: rotate(45deg) scale(1);
    -ms-transform: rotate(45deg) scale(1);
    -webkit-transform: rotate(45deg) scale(1);
    transform: rotate(45deg) scale(1);
  }
}
@-moz-keyframes heartbeat {
  0% {
    -moz-transform: rotate(45deg) scale(1);
    -ms-transform: rotate(45deg) scale(1);
    -webkit-transform: rotate(45deg) scale(1);
    transform: rotate(45deg) scale(1);
  }
  14% {
    -moz-transform: rotate(45deg) scale(1.3);
    -ms-transform: rotate(45deg) scale(1.3);
    -webkit-transform: rotate(45deg) scale(1.3);
    transform: rotate(45deg) scale(1.3);
  }
  28% {
    -moz-transform: rotate(45deg) scale(1);
    -ms-transform: rotate(45deg) scale(1);
    -webkit-transform: rotate(45deg) scale(1);
    transform: rotate(45deg) scale(1);
  }
  42% {
    -moz-transform: rotate(45deg) scale(1.3);
    -ms-transform: rotate(45deg) scale(1.3);
    -webkit-transform: rotate(45deg) scale(1.3);
    transform: rotate(45deg) scale(1.3);
  }
  70% {
    -moz-transform: rotate(45deg) scale(1);
    -ms-transform: rotate(45deg) scale(1);
    -webkit-transform: rotate(45deg) scale(1);
    transform: rotate(45deg) scale(1);
  }
}
@-o-keyframes heartbeat {
  0% {
    -moz-transform: rotate(45deg) scale(1);
    -ms-transform: rotate(45deg) scale(1);
    -webkit-transform: rotate(45deg) scale(1);
    transform: rotate(45deg) scale(1);
  }
  14% {
    -moz-transform: rotate(45deg) scale(1.3);
    -ms-transform: rotate(45deg) scale(1.3);
    -webkit-transform: rotate(45deg) scale(1.3);
    transform: rotate(45deg) scale(1.3);
  }
  28% {
    -moz-transform: rotate(45deg) scale(1);
    -ms-transform: rotate(45deg) scale(1);
    -webkit-transform: rotate(45deg) scale(1);
    transform: rotate(45deg) scale(1);
  }
  42% {
    -moz-transform: rotate(45deg) scale(1.3);
    -ms-transform: rotate(45deg) scale(1.3);
    -webkit-transform: rotate(45deg) scale(1.3);
    transform: rotate(45deg) scale(1.3);
  }
  70% {
    -moz-transform: rotate(45deg) scale(1);
    -ms-transform: rotate(45deg) scale(1);
    -webkit-transform: rotate(45deg) scale(1);
    transform: rotate(45deg) scale(1);
  }
}
@keyframes heartbeat {
  0% {
    -moz-transform: rotate(45deg) scale(1);
    -ms-transform: rotate(45deg) scale(1);
    -webkit-transform: rotate(45deg) scale(1);
    transform: rotate(45deg) scale(1);
  }
  14% {
    -moz-transform: rotate(45deg) scale(1.3);
    -ms-transform: rotate(45deg) scale(1.3);
    -webkit-transform: rotate(45deg) scale(1.3);
    transform: rotate(45deg) scale(1.3);
  }
  28% {
    -moz-transform: rotate(45deg) scale(1);
    -ms-transform: rotate(45deg) scale(1);
    -webkit-transform: rotate(45deg) scale(1);
    transform: rotate(45deg) scale(1);
  }
  42% {
    -moz-transform: rotate(45deg) scale(1.3);
    -ms-transform: rotate(45deg) scale(1.3);
    -webkit-transform: rotate(45deg) scale(1.3);
    transform: rotate(45deg) scale(1.3);
  }
  70% {
    -moz-transform: rotate(45deg) scale(1);
    -ms-transform: rotate(45deg) scale(1);
    -webkit-transform: rotate(45deg) scale(1);
    transform: rotate(45deg) scale(1);
  }
}
body {
  text-align: center;
  padding: 50px;
}

/* Styles for old versions of IE */
.heartbeat {
  font-family: sans-serif;
  font-weight: 100;
}

/* :not(:required) hides this rule from IE9 and below */
.heartbeat:not(:required) {
  -webkit-animation: heartbeat 1300ms ease 0s infinite normal;
  -khtml-animation: heartbeat 1300ms ease 0s infinite normal;
  -moz-animation: heartbeat 1300ms ease 0s infinite normal;
  -ms-animation: heartbeat 1300ms ease 0s infinite normal;
  -o-animation: heartbeat 1300ms ease 0s infinite normal;
  animation: heartbeat 1300ms ease 0s infinite normal;
  display: inline-block;
  position: relative;
  overflow: hidden;
  text-indent: -9999px;
  width: 36px;
  height: 36px;
  -moz-transform: rotate(45deg) scale(1);
  -ms-transform: rotate(45deg) scale(1);
  -webkit-transform: rotate(45deg) scale(1);
  transform: rotate(45deg) scale(1);
  -moz-transform-origin: 50% 50%;
  -ms-transform-origin: 50% 50%;
  -webkit-transform-origin: 50% 50%;
  transform-origin: 50% 50%;
}
.heartbeat:not(:required):after, .heartbeat:not(:required):before {
  position: absolute;
  content: "";
  background: #e87;
}
.heartbeat:not(:required):before {
  -moz-border-radius-topleft: 12px;
  -webkit-border-top-left-radius: 12px;
  border-top-left-radius: 12px;
  -moz-border-radius-bottomleft: 12px;
  -webkit-border-bottom-left-radius: 12px;
  border-bottom-left-radius: 12px;
  top: 12px;
  left: 0;
  width: 36px;
  height: 24px;
}
.heartbeat:not(:required):after {
  -moz-border-radius-topleft: 12px;
  -webkit-border-top-left-radius: 12px;
  border-top-left-radius: 12px;
  -moz-border-radius-topright: 12px;
  -webkit-border-top-right-radius: 12px;
  border-top-right-radius: 12px;
  top: 0;
  left: 12px;
  width: 24px;
  height: 12px;
}

<span class="heartbeat">Loading...</span>

To understand the principle...

Using variables in CSS is not possible at the moment and is unlikely to be possible anytime soon.

This is only available using CSS pre-processors, such as less or sass.

jsfiddle and codepen allow you to use scss (sass) in the CSS panel and correctly output the processed CSS when rendering.

sass.js is a library that allows you to use .sass files in <link> tags and processes them into valid CSS at load time.

It is likely that major browsers will soon be capable of processing .scss, .sass or .less files natively and it is already possible by using browser extensions.

This, however, does not mean CSS will ever support variables.

来源：https://stackoverflow.com/questions/42164133/css-animated-icon-resize

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css

css3

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