create_css.sh

cat <<EOF
@keyframes flakeH {
	from { left: 0%; }
	to { left: 100%; }
}

@keyframes flakeV {
	from { top: 0%; }
	to { top: 100%; }
}

@-webkit-keyframes flakeH {
	from { left: 0%; }
	to { left: 100%; }
}

@-webkit-keyframes flakeV {
	from { top: 0%; }
	to { top: 100%; }
}

@-moz-keyframes flakeH {
	from { left: 0%; }
	to { left: 100%; }
}

@-moz-keyframes flakeV {
	from { top: 0%; }
	to { top: 100%; }
}

#snow i, #snow b {
	font-style:normal;
	font-weight:normal;
}

#snow i {
	pointer-events: none;
	animation: flakeV 0s linear 0s infinite; /* Chrome, Safari, Opera */
	-webkit-animation: flakeV 0s linear 0s infinite; /* Chrome, Safari, Opera */
	-moz-animation: flakeV 0s linear 0s infinite; /* Chrome, Safari, Opera */
	position:fixed;
	top:0;
}
#snow b {
	position:absolute;
	color: white;
	text-shadow: 0px 0px 1px black;
	animation: flakeH 0s ease-in-out 0s infinite alternate; /* Chrome, Safari, Opera */
	-webkit-animation: flakeH 0s ease-in-out 0s infinite alternate; /* Chrome, Safari, Opera */
	-moz-animation: flakeH 0s ease-in-out 0s infinite alternate; /* Chrome, Safari, Opera */
}

EOF

rand() {
	r=`od -N1 -An -i /dev/urandom`
	echo "$1 + $r%$2" | bc
}
rand2() {
	r=`od -N1 -An -i /dev/urandom`
	r2=`od -N1 -An -i /dev/urandom`
	if [ $2 -eq 0 ]; then
		echo "$1; $r2%(10^$3)" | bc | tr "\n" '.' | sed "s/\.$//"
	else
		echo "$1 + $r%$2; $r2%(10^$3)" | bc | tr "\n" '.' | sed "s/\.$//"
	fi
}

for i in `seq 1 20`; do
	left=`rand 0 100`
	duration1=`rand2 20 20 1`
	duration2=`rand2 1 5 2`
	delay=`rand 0 20`
	width=`rand 10 30`
	size=`rand 6 6`
	cat <<EOF
#snow i:nth-child($i) {
	left:${left}%;
	animation-duration:${duration1}s; -webkit-animation-duration:${duration1}s; -moz-animation-duration:${duration1}s;
	animation-delay:${delay}s; -webkit-animation-delay:${delay}s; -moz-animation-delay:${delay}s;
	width:${width}pt;
	font-size:${size}pt;
}
#snow i:nth-child($i) b {
	animation-duration:${duration2}s; -webkit-animation-duration:${duration2}s; -moz-animation-duration:${duration2}s;
}

EOF
done