// I created a 20x20px .png cookie image to add to my cookie notice button. Feel free to use the link below to download mine and upload it to your own Squarespace website. Or create your own. Get creative! :) Upload this image in Design > Custom CSS > Manage Custom Files to use it in your CSS.
.cookie-notice button:before {
content: url(https://static1.squarespace.com/static/5ab9b2bd4cde7ab8d5a90e2c/t/5aff0c3c88251b88948c0edb/1526664252828/cookie-small.png);
position: relative;
top: 2px;
margin-right: 5px;
vertical-align: middle;
}