wp-calypso/client/blocks/inline-help/placeholder-lines.scss

// PlaceholderLines component
.inline-help__results-placeholder {
	margin: 16px;
	min-height: 120px;
}

.inline-help__results-placeholder-item {
	height: 16px;
	margin: 16px 0;
	border-radius: 16px; /* stylelint-disable-line scales/radii */
	background-color: var(--color-neutral-0);
	color: transparent;
	animation: inline-help__results-placeholder-loading 2s cubic-bezier(0.175, 0.885, 0.32, 1.275) infinite;
	animation-delay: 0s;

	&:nth-child(1) {
		animation-delay: -1.3s;
	}

	&:nth-child(2) {
		animation-delay: -2.5s;
	}

	&:nth-child(3) {
		animation-delay: -3.8s;
	}

	&::after {
		content: "\00a0";
	}
}

@keyframes inline-help__results-placeholder-loading {
	0% {
		opacity: 0.3;
		width: 65%;
	}
	25% {
		opacity: 0.6;
		width: 90%;
	}
	50% {
		opacity: 0.5;
		width: 18%;
	}
	75% {
		opacity: 0.8;
		width: 75%;
	}
	100% {
		opacity: 0.3;
		width: 65%;
	}
}