使用codepen创建焰火动画的问题

Question

这是我要测试的CodePen。它创建了一个美丽的烟花动画但是，当我创建一个HTML文件和一个CSS文件并从CodePen复制并粘贴相同的代码时，没有任何反应。我错过了什么？

CodePen：https://codepen.io/yshlin/pen/ylDEk

我的文件：

我的Html文件名为Index.html：

 <link rel="stylesheet" href="Style.css">
    <div class="pyro">
  <div class="before"></div>
  <div class="after"></div>
</div>

CSS文件名为Style.css

$particles: 50;
$width: 500;
$height: 500;

// Create the explosion...
$box-shadow: ();
$box-shadow2: ();
@for $i from 0 through $particles {
  $box-shadow: $box-shadow,
               random($width)-$width / 2 + px
               random($height)-$height / 1.2 + px
               hsl(random(360), 100, 50);
  $box-shadow2: $box-shadow2, 0 0 #fff
}
@mixin keyframes ($animationName) {
    @-webkit-keyframes #{$animationName} {
        @content;
    }

    @-moz-keyframes #{$animationName} {
        @content;
    }

    @-o-keyframes #{$animationName} {
        @content;
    }

    @-ms-keyframes #{$animationName} {
        @content;
    }

    @keyframes #{$animationName} {
        @content;
    }
}

@mixin animation-delay ($settings) {
    -moz-animation-delay: $settings;
    -webkit-animation-delay: $settings;
    -o-animation-delay: $settings;
    -ms-animation-delay: $settings;
    animation-delay: $settings;
}

@mixin animation-duration ($settings) {
    -moz-animation-duration: $settings;
    -webkit-animation-duration: $settings;
    -o-animation-duration: $settings;
    -ms-animation-duration: $settings;
    animation-duration: $settings;
}

@mixin animation ($settings) {
    -moz-animation: $settings;
    -webkit-animation: $settings;
    -o-animation: $settings;
    -ms-animation: $settings;
    animation: $settings;
}

@mixin transform ($settings) {
    transform: $settings;
    -moz-transform: $settings;
    -webkit-transform: $settings;
    -o-transform: $settings;
    -ms-transform: $settings;
}

body {
  margin:0;
  padding:0;
  background: transparent;
  overflow: hidden;
}

.pyro > .before, .pyro > .after {
  position: absolute;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  box-shadow: $box-shadow2;
  @include animation((1s bang ease-out infinite backwards, 1s gravity ease-in infinite backwards, 5s position linear infinite backwards));
}

.pyro > .after {
  @include animation-delay((1.25s, 1.25s, 1.25s));
  @include animation-duration((1.25s, 1.25s, 6.25s));
}

@include keyframes(bang) {
  to {
    box-shadow:$box-shadow;
  }
}

@include keyframes(gravity)  {
  to {
    @include transform(translateY(200px));
    opacity: 0;
  }
}

@include keyframes(position) {
  0%, 19.9% {
    margin-top: 10%;
    margin-left: 40%;
  }
  20%, 39.9% {
    margin-top: 40%;
    margin-left: 30%;
  }
  40%, 59.9% {  
    margin-top: 20%;
    margin-left: 70%
  }
  60%, 79.9% {  
    margin-top: 30%;
    margin-left: 20%;
  }
  80%, 99.9% {  
    margin-top: 30%;
    margin-left: 80%;
  }
}

Answer 1

他正在使用sass，你必须编译文件以在CSS中转换它，你可以看到编译的CSS点击CSS框右上角的下拉列表