zoubingwu/fireworks.scss

## fireworks.scss
// original: https://codepen.io/yshlin/pen/ylDEk

$particles: 60;
$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: #000;
  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%;
  }
}

## index.html
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <link rel="stylesheet" href="./fireworks.scss">
</head>
<body>
  <div class="pyro">
    <div class="before"></div>
    <div class="after"></div>
  </div>
</body>
</html>
	// original: https://codepen.io/yshlin/pen/ylDEk

	$particles: 60;
	$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: #000;
	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%;
	}
	}
	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta charset="UTF-8">
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<meta http-equiv="X-UA-Compatible" content="ie=edge">
	<title>Document</title>
	<link rel="stylesheet" href="./fireworks.scss">
	</head>
	<body>
	<div class="pyro">
	<div class="before"></div>
	<div class="after"></div>
	</div>
	</body>
	</html>