wp-calypso/client/blocks/comments/autoresizing-form-textarea.scss

.expanding-area {
	position: relative;
	$initial-focused-height: 70px;

	pre,
	textarea {
		max-height: 400px;
		min-height: 33px;
		margin: 0;
		padding: 5px;
		font-size: $font-body-small;
		font-family: $sans;
		line-height: 21px;

		white-space: pre-wrap;
		word-wrap: break-word;
		word-break: break-word;
	}

	textarea {
		position: absolute;
		top: 0;
		left: 0;
		height: 100%;
		resize: none;
	}

	pre {
		border: 1px solid var(--color-neutral-light);
		box-sizing: border-box;
		display: block;
		visibility: hidden;
	}

	&.focused {
		min-height: $initial-focused-height;
	}
}