Add this html code to a code block on a page or to settings advanced code injection header:
<style>
/* customizable snowflake styling */
.snowflake {
color: #fff;
font-size: 1em;
font-family: Arial, sans-serif;
text-shadow: 0 0 5px #000;
}
@-webkit-keyframes snowflakes-fall{0%{top:-10%}100%{top:100%}}@-webkit-keyframes snowflakes-shake{0%,100%{-webkit-transform:translateX(0);transform:translateX(0)}50%{-webkit-transform:translateX(80px);transform:translateX(80px)}}@keyframes snowflakes-fall{0%{top:-10%}100%{top:100%}}@keyframes snowflakes-shake{0%,100%{transform:translateX(0)}50%{transform:translateX(80px)}}.snowflake{position:fixed;top:-10%;z-index:9999;-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;cursor:default;-webkit-animation-name:snowflakes-fall,snowflakes-shake;-webkit-animation-duration:10s,3s;-webkit-animation-timing-function:linear,ease-in-out;-webkit-animation-iteration-count:infinite,infinite;-webkit-animation-play-state:running,running;animation-name:snowflakes-fall,snowflakes-shake;animation-duration:10s,3s;animation-timing-function:linear,ease-in-out;animation-iteration-count:infinite,infinite;animation-play-state:running,running}.snowflake:nth-of-type(0){left:1%;-webkit-animation-delay:0s,0s;animation-delay:0s,0s}.snowflake:nth-of-type(1){left:10%;-webkit-animation-delay:1s,1s;animation-delay:1s,1s}.snowflake:nth-of-type(2){left:20%;-webkit-animation-delay:6s,.5s;animation-delay:6s,.5s}.snowflake:nth-of-type(3){left:30%;-webkit-animation-delay:4s,2s;animation-delay:4s,2s}.snowflake:nth-of-type(4){left:40%;-webkit-animation-delay:2s,2s;animation-delay:2s,2s}.snowflake:nth-of-type(5){left:50%;-webkit-animation-delay:8s,3s;animation-delay:8s,3s}.snowflake:nth-of-type(6){left:60%;-webkit-animation-delay:6s,2s;animation-delay:6s,2s}.snowflake:nth-of-type(7){left:70%;-webkit-animation-delay:2.5s,1s;animation-delay:2.5s,1s}.snowflake:nth-of-type(8){left:80%;-webkit-animation-delay:1s,0s;animation-delay:1s,0s}.snowflake:nth-of-type(9){left:90%;-webkit-animation-delay:3s,1.5s;animation-delay:3s,1.5s}.snowflake:nth-of-type(10){left:25%;-webkit-animation-delay:2s,0s;animation-delay:2s,0s}.snowflake:nth-of-type(11){left:65%;-webkit-animation-delay:4s,2.5s;animation-delay:4s,2.5s}
</style>
<div class="snowflakes" aria-hidden="true">
<div class="snowflake">
❅
</div>
<div class="snowflake">
❆
</div>
<div class="snowflake">
❅
</div>
<div class="snowflake">
❆
</div>
<div class="snowflake">
❅
</div>
<div class="snowflake">
❆
</div>
<div class="snowflake">
❅
</div>
<div class="snowflake">
❆
</div>
<div class="snowflake">
❅
</div>
<div class="snowflake">
❆
</div>
<div class="snowflake">
❅
</div>
<div class="snowflake">
❆
</div>
</div>
