wp-calypso/packages/components/src/searchable-dropdown/style.scss

.searchable-dropdown {
	// TODO: We will have to figure out and adopt standard Calypso styling for the combobox control.
	// So we do not have to override so many styles here or in the future.
	.components-base-control__field.components-base-control__field {
		margin: 0;
	}

	input.components-combobox-control__input[type="text"] {
		font-size: 1rem;
		line-height: 1.5;
		padding: 7px 14px;
	}

	.components-combobox-control__suggestions-container .components-flex {
		border: 1px solid var(--color-neutral-10);
		border-radius: 2px;
		background-color: var(--color-surface);
		transition: all 0.15s ease-in-out;
		height: 40px;
	}

	.components-combobox-control__suggestions-container:focus-within {
		border-color: var(--color-primary);
		box-shadow: 0 0 0 2px var(--color-primary-10);
		outline: none;
	}

	.components-combobox-control__suggestions-container {
		border: none;
	}

	.components-form-token-field__suggestion.is-selected {
		background-color: var(--color-primary);
	}

	.components-form-token-field__suggestions-list li {
		padding: 10px;
		font-size: 1rem;
	}
}

.searchable-dropdown.is-disabled {
	.components-base-control__field.components-base-control__field {
		background: var(--color-neutral-0);
	}

	input.components-combobox-control__input[type="text"] {
		border-color: var(--color-neutral-0);
		color: var(--color-neutral-20);
		opacity: 1;
		-webkit-text-fill-color: var(--color-neutral-20);

		&:hover {
			cursor: default;
		}

		&::placeholder {
			color: var(--color-neutral-20);
		}
	}
}