woocommerce/plugins/woocommerce-blocks/assets/js/base/components/panel/style.scss

.wc-blocks-components-panel.has-border {
	border-top: 1px solid $core-grey-light-600;
	border-bottom: 1px solid $core-grey-light-600;
	margin-bottom: -1px;
}

.wc-blocks-components-panel__button {
	&,
	&:hover,
	&:focus,
	&:active {
		@include reset-box();
		@include reset-typography();
		background: transparent;
		box-shadow: none;
		height: auto;
		line-height: 1;
		margin-bottom: em(6px);
		margin-top: em(6px);
		padding-bottom: em($gap-small - 6px);
		padding-right: #{24px + $gap-smaller};
		padding-top: em($gap-small - 6px);
		position: relative;
		text-align: left;
		width: 100%;
	}

	> .wc-blocks-components-panel__button-icon {
		position: absolute;
		right: 0;
		top: 50%;
		transform: translateY(-50%);
		width: auto;
	}
}

.wc-blocks-components-panel__content {
	padding-bottom: em($gap);
}

.theme-twentytwenty .wc-blocks-components-panel__button {
	background: transparent;
}