style.scss

// Apply max-width to floated items that have no intrinsic width
.wp-block[data-align="left"] > [data-type="core/embed"],
.wp-block[data-align="right"] > [data-type="core/embed"],
.wp-block-embed.alignleft,
.wp-block-embed.alignright {
	// Instagram widgets have a min-width of 326px, so go a bit beyond that.
	max-width: 360px;
	width: 100%;

	// Unless these have a min-width, they collapse when floated.
	.wp-block-embed__wrapper {
		min-width: $break-zoomed-in;
	}
}

// Supply a min-width when inside a cover block, to prevent it from collapsing.
.wp-block-cover .wp-block-embed {
	min-width: 320px;
	min-height: 240px;
}

.wp-block-embed {
	// Supply caption styles to embeds, even if the theme hasn't opted in.
	// Reason being: the new markup, figcaptions, are not likely to be styled in the majority of existing themes,
	// so we supply the styles so as to not appear broken or unstyled in those.
	figcaption {
		@include caption-style();
	}
	// The embed block is in a `figure` element, and many themes zero this out.
	// This rule explicitly sets it, to ensure at least some bottom-margin in the flow.
	margin-bottom: 1em;

	// Don't allow iframe to overflow it's container.
	iframe {
		max-width: 100%;
	}
}

.wp-block-embed__wrapper {
	position: relative;
}

// Add responsiveness to embeds with aspect ratios.
.wp-embed-responsive .wp-has-aspect-ratio {
	.wp-block-embed__wrapper::before {
		content: "";
		display: block;
		padding-top: 50%; // Default to 2:1 aspect ratio.
	}

	iframe {
		position: absolute;
		top: 0;
		right: 0;
		bottom: 0;
		left: 0;
		height: 100%;
		width: 100%;
	}
}

.wp-embed-responsive {
	.wp-embed-aspect-21-9 .wp-block-embed__wrapper::before {
		padding-top: 42.85%; // 9 / 21 * 100
	}

	.wp-embed-aspect-18-9 .wp-block-embed__wrapper::before {
		padding-top: 50%; // 9 / 18 * 100
	}

	.wp-embed-aspect-16-9 .wp-block-embed__wrapper::before {
		padding-top: 56.25%; // 9 / 16 * 100
	}

	.wp-embed-aspect-4-3 .wp-block-embed__wrapper::before {
		padding-top: 75%; // 3 / 4 * 100
	}

	.wp-embed-aspect-1-1 .wp-block-embed__wrapper::before {
		padding-top: 100%; // 1 / 1 * 100
	}

	.wp-embed-aspect-9-16 .wp-block-embed__wrapper::before {
		padding-top: 177.77%; // 16 / 9 * 100
	}

	.wp-embed-aspect-1-2 .wp-block-embed__wrapper::before {
		padding-top: 200%; // 2 / 1 * 100
	}
}