style.css

html {
	font-size:62.5%;
}

body {
	display: flex;
	flex-direction: column;
	min-height: 100vh;
	margin: 0;
	font-size: 1.6rem;
	text-align:center;
}

body > header,
body > footer {
	padding: 1.2rem;
	color: white;
	background-color: #006400;

}
body > header {
	margin-bottom: 1.6rem;
	border-radius: 0 0 3.2rem 3.2rem;
}
body > footer {
	margin-top: 1.6rem;
	border-radius: 3.2rem 3.2rem 0 0;
}

main {
	flex-grow: 1;
}

section {
	margin-bottom: 3.2rem;
}

nav,
aside {
	margin-top: 3.2rem;
	border-top: 0.8rem solid #006400;
	border-radius: 3.2rem 3.2rem 0 0;
	padding: 0.8rem 1.6rem;
}
aside {
	border-color: #bbbbbb;
	color: #444444;
}

h1 {
	font-size: 1.6rem;
	margin:0;
	padding:0;
}

h2 {
	margin-top: 1.6rem;
	margin-bottom: 0.8rem;
}

h3 {
	margin-top: 0;
	margin-bottom: 0.8rem;
}

pre {
    white-space: pre-wrap;
}

a {
	color: #006400;
}
header a {
	color: inherit;
}

dt::after {
	content: ": ";
}

dt, dd {
	display: inline;
}

body > footer a,
body > nav li:nth-child(odd) a,
.testcases .sectionContent a {
	color: inherit;
}

nav ol {
	display: flex;
	flex-wrap: wrap;
	align-items: flex-end;
	margin: 0;
	padding: 0;
}

nav li {
	display: block;
	flex-grow: 1;
	margin-bottom: 0.8rem;
	border: 0.1rem solid #006400;
	padding: 1.6rem;
}
nav li:nth-child(odd) {
	background-color: #006400;
	color: white;
}
nav li.active {
	padding-top:3.2rem;
	border-radius: 1.6rem 1.6rem 0 0;
}

main header,
main footer {
    margin: 0;
}

main .sectionContent {
    display: flex;
    flex-wrap: wrap;
	align-content: flex-start;
	overflow: hidden;
}

main .sectionContent section {
    min-height:40px;
    margin: 0.8rem 1.6rem;
    border: 0.1rem solid #006400;
	border-left: none;
	border-right: none;
	border-radius: 3.2rem;
	padding: 0 2rem;
    text-align:center;
    flex-grow: 1;
    position: relative;
}
main .sectionContent section:last-child {
    flex-grow: 0;
}
main .sectionContent section:only-child {
	flex-grow: 1;
}

main .sectionContent h3 {
	margin: 1rem 0;
}

.testcases div h2:before,
.testcases div h3:before,
.testcases div h4:before {content:'Media feature “'}
.testcases div h2:after,
.testcases div h3:after,
.testcases div h4:after {content:'” is not applicable'}

.deprecated:after,
.proprietary:after {
    display: block;
    position: absolute;
    margin: 0;
    top: -1rem;
    right: -3rem;
    transform: rotate(27deg);
    transform-origin: left top 0;
    padding: 0.2em 0.4em;
    border-radius: 0.4em;
    font-size: 1.6rem;
    font-weight: bold;
}
.deprecated:after {
	content: 'Deprecated';
	color: white;
	background-color: red;
}
.proprietary:after {
	content: 'Proprietary';
	color: black;
	background-color: yellow;
}

@media all and (max-width: 400px) {
    pre {
        text-align: left;
        text-align-last: right;
    }
}

@media all and (max-width: 800px) {
    main .sectionContent section:last-child {
        flex-grow: 1;
    }
}

@media all and (screen-spanning: single-fold-vertical) {
	body {
		display: grid;
  	grid-template-areas:
        "header nav"
        "main nav"
        "main aside"
        "main footer";
  	grid-template-columns: env(fold-left) calc(100% - env(fold-left) - env(fold-width));
  	grid-template-rows: auto auto 1fr auto;
  	grid-gap: 0px env(fold-width);
	}

	header {
		grid-area: header;
	}

	main {
		grid-area: main;
	}

	nav {
		grid-area: nav;
		margin-top: 0;
	}

	aside {
		grid-area: aside;
	}

	footer {
		grid-area: footer;
	}
}