wp-calypso/client/assets/stylesheets/shared/_loading.scss

.wpcom-site__logo {
	fill: var(--color-neutral-10);
	color: var(--color-neutral-10);
	position: fixed;
	top: 50%;
	left: 50%;
	transform: translate(-50%, -50%);

	path {
		fill: var(--color-neutral-10);
	}

	@include breakpoint-deprecated( ">960px" ) {
		width: 100px;
		height: 100px;
	}
}

.wpcom__loading {
	--wp-components-color-foreground: #3858e9;
	padding: 1em;
	max-width: 540px;
	margin: 32vh auto 0;

	&.wpcom-loading__boot {
		margin: calc( 32vh + 60px ) auto 0;
	}

	.wpcom__loading-title {
		height: 40px;
		line-height: 40px;
		margin: 0;
	}

	.wpcom__loading-progress-bar {
		margin: 46px auto 0 auto;
	}
}

.is-section-signup {
	.wpcom-loading__boot {
		margin: calc( 32vh + 12px ) auto 0;
	}
}

.wpcom__loading-ellipsis {
	display: inline-block;
	position: relative;
	width: 80px;
	height: 80px;

	&.wpcom-site__logo {
		position: fixed;
	}

	> div {
		position: absolute;
		top: 33px;
		width: 13px;
		height: 13px;
		border-radius: 50%;
		background: var(--studio-gray-60);
		animation-timing-function: cubic-bezier(0, 1, 1, 0);

		&:nth-child(1) {
			left: 8px;
			animation: wpcom__loading-ellipsis-grow 0.6s infinite;
		}
		&:nth-child(2) {
			left: 8px;
			animation: wpcom__loading-ellipsis-move 0.6s infinite;
		}
		&:nth-child(3) {
			left: 32px;
			animation: wpcom__loading-ellipsis-move 0.6s infinite;
		}
		&:nth-child(4) {
			left: 56px;
			animation: wpcom__loading-ellipsis-shrink 0.6s infinite;
		}
	}
}

@keyframes wpcom__loading-ellipsis-grow {
	0% {
		transform: scale(0);
	}
	100% {
		transform: scale(1);
	}
}
@keyframes wpcom__loading-ellipsis-move {
	0% {
		transform: translate(0, 0);
	}
	100% {
		transform: translate(24px, 0);
	}
}
@keyframes wpcom__loading-ellipsis-shrink {
	0% {
		transform: scale(1);
	}
	100% {
		transform: scale(0);
	}
}