Copy the following code:
.product-list .pl-variants .pl-variant-option.selected {
background: #00d81e !important;
border-color: #00d81e !important;
}
Paste it under CUSTOM CODES > CUSTOM CSS
Copy the following code:
.product-list .pl-variants .pl-variant-option.selected {
background: #00d81e !important;
border-color: #00d81e !important;
}
Paste it under CUSTOM CODES > CUSTOM CSS