Accessible Accordion: Basic accordion styling

accessible-accordion-basic-accordion-styling.css

details {
	--curtain-border-color: #334455;
	--curtain-background-color: #223344;
	--curtain-color: #ffffff;

	max-width: 30rem;
	border: 1px solid var(--curtain-border-color);
	color: var(--curtain-color);
  	overflow: hidden;
}

summary {
	position: relative;
	display: block;
	padding: 1rem 3.5rem 1rem 1rem;
	background: var(--curtain-background-color);
}

summary::-webkit-details-marker {
	display: none;
}

summary:focus {
	outline: none;
	box-shadow: inset 0 0 0.25em 0.125em #08f;
}

summary:after {
	content: "";
	position: absolute;
	top: 1.375rem;
	right: 1rem;

	display: inline-block;
	vertical-align: top;
	width: 0;
	height: 0;

	border: 0.5rem solid transparent;
	border-top-color: #ffffff;
	border-bottom-width: 0;

	transition: transform 0.5s;
}

details[open] summary:after {
	transform: rotateX(180deg);
}

.curtain__content {
	padding: 1rem;
}