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

.wc-block-components-form .wc-block-components-select,
.wc-block-components-select {
	height: 3em;
	position: relative;

	label.components-custom-select-control__label {
		@include reset-typography();
		@include font-size(regular);
		line-height: 1.375; // =22px when font-size is 16px.
		position: absolute;
		transform: translateY(0.75em);
		transform-origin: top left;
		transition: all 200ms ease;
		color: $gray-700;
		z-index: 1;
		margin: 0 0 0 #{$gap + 1px};
		overflow: hidden;
		text-overflow: ellipsis;
		max-width: calc(100% - #{2 * $gap});
		white-space: nowrap;

		.has-dark-controls & {
			color: $input-placeholder-dark;
		}
		@media screen and (prefers-reduced-motion: reduce) {
			transition: none;
		}
	}

	&.is-active label {
		transform: translateY(#{$gap-smallest}) scale(0.75);
	}

	&.has-error {
		.components-custom-select-control__button {
			&,
			&:hover,
			&:focus,
			&:active {
				border-color: $alert-red;
			}
			&:focus {
				outline: 1px dotted $alert-red;
				outline-offset: 2px;
			}
		}
	}

	&.has-error label {
		color: $alert-red;
	}

	.components-custom-select-control__button {
		&,
		&:hover,
		&:focus,
		&:active {
			@include font-size(regular);
			background: #fff;
			box-shadow: none;
			color: $input-text-active;
			font-family: inherit;
			font-weight: normal;
			height: 3em;
			letter-spacing: inherit;
			line-height: 1;
			overflow: hidden;
			padding: em($gap-large) $gap em($gap-smallest);
			text-align: left;
			text-overflow: ellipsis;
			text-transform: none;
			white-space: nowrap;
			width: 100%;
			opacity: initial;
			border-radius: 4px;
			.has-dark-controls & {
				background: $input-background-dark;
				border-color: $input-border-dark;
				color: $input-text-dark;
			}
		}
	}

	.components-custom-select-control__button-icon {
		right: #{$gap - 4px};
		.has-dark-controls & {
			fill: $input-text-dark;
		}
	}

	.components-custom-select-control__menu {
		background-color: $select-dropdown-light;
		margin: 0;
		max-height: 300px;
		overflow: auto;
		color: $input-text-active;

		// Required by IE11.
		&:empty {
			display: none;
		}
		.has-dark-controls & {
			background-color: $select-dropdown-dark;
			color: $input-text-dark;
		}
	}

	.components-custom-select-control__item {
		@include font-size(regular);
		margin-left: 0;
		padding-left: $gap;
		&:hover,
		&:focus,
		&.is-highlighted {
			.has-dark-controls & {
				background-color: $select-item-dark;
			}
		}
	}

	.components-custom-select-control__item-icon {
		display: none;
	}
}

.theme-twentytwentyone {
	// Extra classes for specificity.
	&.theme-twentytwentyone.theme-twentytwentyone .components-custom-select-control__button {
		background-color: #fff;
		color: $input-text-active;
	}

	&.is-dark-theme {
		// If the theme is in dark mode, as well as the block, then this selector will match.
		.has-dark-controls {
			.components-custom-select-control__item {
				color: $input-text-dark;
			}
		}

		// If the theme is in dark mode, but the block isn't, then this selector will match.
		.components-custom-select-control__item {
			color: $input-text-active;
		}
	}
}

.theme-twentyseventeen {
	// Extra classes for specificity.
	&.theme-twentyseventeen.theme-twentyseventeen {
		.components-custom-select-control__button {
			background-color: $select-dropdown-light;
			color: $input-text-active;
		}
		.has-dark-controls {
			.components-custom-select-control__button {
				background-color: $select-dropdown-dark;
				color: $input-text-dark;
			}
		}
	}
}