#hex li {
list-style-type: none;
position: relative;
float: left;
width: 25%;
padding: 0 0 30% 0;
-o-transform: rotate(-60deg) skewY(30deg);
-moz-transform: rotate(-60deg) skewY(30deg);
-webkit-transform: rotate(-60deg) skewY(30deg);
-ms-transform: rotate(-60deg) skewY(30deg);
transform: rotate(-60deg) skewY(30deg);
background-color: #4c4177;
background-image: linear-gradient(315deg, #4c4177 0%, #2a5470 74%);
box-shadow: 5px 5px 5px 5px yellow
}
.clear:after {
content: "";
display: block;
clear: both;
}
<ul id="hex" class="clear">
<li></li>
</ul>
Your code was using sass not css . Adapted from
https://www.codesmite.com/article/how-to-create-pure-css-hexagonal-grids