Hello,

1. Please, navigate to Theme Settings -> Custom CSS, and remove the custom CSS code that is shown on the below screenshot.

https://monosnap.com/file/aCqpH71AQDDZXKqwD6abQgOqN0zKMP

2. Please, try to use the below code for adding the border to the size swatches.

.woodmart-woocommerce-layered-nav .wd-filter-list .wc-layered-nav-term.with-swatch-text a {
	border: 1px solid rgba(0,0,0,0.15);
	border-radius: 3px;
	padding: 3px;
}

Kind Regards