/* CSS that adds the bare minimum for a simple layout.
 * Nothing here exists purely for aesthetics; everything addresses a
 * specific a11y, compatibility, or critical
 * usability need.
 *
 * I also don't use any classes except for image presentation. (e.g. to
 * specify that an image should have pixelated rendering or be inverted
 * in dark mode).
 * My HTML contains microformats2 classnames for IndieWeb parsers, but I
 * don't actually use those for styling.
 *
 * To keep myself from caring about minute details, I limited myself to
 * only defining spacing in increments of .125em. Pixels are 1px or
 * multiples of 3px; percentages are in increments of 2.5%. This also
 * improves compression. No more "finding the perfect value".
 *
 * I cite WCAG 2.2 success criteria with "SC". I also tried to meet
 * the Google a11y requirement of 48px tap targets separated by atl
 * 8px, excluding inline links. This involved increasing font size,
 * padding, line-height, and margins. */

html {
	/* Mobile screens benefit from greater line-spacing so links are
	 * further apart. Dyslexic users prefer the spacing too.
	 * Necessary to meet SC 1.4.8.
	 * <100dpi screens: sans-serif is better. Why did browsers settle
	 * on serif being the default?? */
	font: 100%/1.5 sans-serif;
	/* Nearly every page on my site is taller than the viewport.
	 * Paint the scrollbar ASAP to prevent layout shifts. */
	overflow-y: scroll;
}

/* This should not take effect on printouts, to save paper. */
@media screen {
	body {
		/* Default font sizes are one-size-fits-all; they're optimized for a
		 * wide variety of complex pages. For single-column websites like
		 * mine, it's ideal to bump it up ever so slightly. This also makes
		 * <sup>, <sub>, <small>, etc. large enough to have decent contrast
		 * with minimal adjustment, and makes tap-targets larger.
		 * Only do this on screen, since printouts already improve legibility
		 * and cost paper + ink. */
		font-size: 107.5%;

		/* Aligning to the center with space on both sides prevents accidental
		* link activation on tablets, and is a common practice that users are
		* more used to for articles. */
		margin: auto;

		/* WCAG recommends a max line width. Not everyone can resize the
		 * viewport. This isn't for large blocks of text yet, so we don't have
		 * to go by SC 1.4.8.
		 * 45em = lowest acceptable width for titles, nav, footers, etc */
		max-width: 45em;

		/* Phone cases can cover the edges. Swipe-from-edge navigations
		 * should not conflict with the page elements. Focus outlines for
		 * heavily-padded nav links should not be cut-off. All three concerns
		 * are addressed by adding some body padding.
		 * I followed Google's a11y recommendations of "at least 8px space
		 * between tappables" by creating margins/paddings between nav links;
		 * re-use that same amount of space here. 24px is what it takes to
		 * create atl 48px of non-interactive space on <ul> and <ol> elements
		 * containing lists of interactives.
		 * Don't use relative units here; this margin shouldn't scale with
		 * zoom, or else text will get narrower with zoom. */
		padding: 0 24px;
	}

	/* 45em is too wide for long body text.
	 * Typically meets SC 1.4.8, plus or minus a few characters. */
	div[itemprop="articleBody"] {
		margin: auto;
		max-width: 36em;
	}

	/* Compensate for misalignment and wasted space caused by padding
	 * and margin adjustments in nav children made to meet SC 2.5.5 */
	header > nav,
	footer > nav {
		margin: 0 0 -.75em -.25em;
	}

	summary {
		/* The tappable region of a <summary> extends across the page.
		 * we need to tell users that the full space is interactive.
		 * Use a border for that. */
		border: 1px solid #999;
		/* It's not obvious that a <summary> has button semantics.
		 * "cursor: pointer" is used on MDN, web.dev, GitHub, gov.uk, and
		 * others so it's not "novel" and won't surprise users. */
		cursor: pointer;
	}

	/* If we have a list of disclosure widgets, we need some
	 * non-interactive space on the screen that's safe to tap. */
	li details {
		margin: .5em .25em;
	}

	/* Google a11y: ensure tap targets have >=8px space between them */
	nav li,
	li details li {
		padding: 1em 0;
	}

	/* SC 2.5.5, Google a11y: Increase tap target size a bit */
	summary,
	li > a {
		padding: .875em .25em;
	}

	nav li ol {
		/* Don't duplicate bottom space: the last list item in the nested
		 * list and the list item that is the entire nested list will both
		 * have bottom padding */
		margin-bottom: -1em;
		/* Prevent nested lists from overlapping */
		padding-top: 1em;
	}
}

/* narrow screens: reduce list indentation, hyphenate nested lists
 * touch screens: lists of links should be easy to tap so give them
 * some spacing (partial SC 2.5.5). There should be non-interactive
 * space to the left that's safe to tap. */
dd,
ol,
ul {
	margin: 0;
	padding-left: 1.625em;
}

ol ol,
ul ul {
	-webkit-hyphens: auto;
	hyphens: auto;
	padding-left: 1em;
}

/* Save some space and paper by making the site nav and footer links
 * single-line without bullets. The title should be visible in the fold
 * on most screens so users can identify the current page. */

/* Step 1 to making the single-line nav: remove the bullet padding. */
nav ul {
	padding: 0
}

/* step 2: remove bullets and make elements inline.
 * Also: bump up the line-height and margins to increase space
 * between tap-targets (SC 2.5.5). Google a11y guidelines require 8 CSS
 * pixels between tap targets. */
nav ul li {
	display: inline-block;
	margin-right: .375em;
}


/* narrow screens: reduce margin for blockquotes a lot, using
 * a border instead. Put it on the left and right to make it
 * LTR/RTL-neutral, for machine translators that change text
 * direction (e.g. the one in Edge). */
blockquote {
	border-left: 3px solid;
	margin: 0;
	padding: 0 1em;
}

/* Narrow screens: allow hyphenating titles
 * I can't add soft hyphens to these. */
h1 {
	-webkit-hyphens: auto;
	hyphens: auto;
}

/* Very narrow screens: full hyphenation */
@media (max-width: 13em) {
	body {
		font-size: 100%;
		-webkit-hyphens: auto;
		hyphens: auto;
		padding: 0 8px;
	}
}

/* <kbd> should be distinguished from <code> and surrounding text
 * in a way beyond font-face; at least two visual distinctions needed
 * Also, Small text is easier to read when slightly bolder.
 * This is important in the dark theme where I set my own colors and
 * try to maintain good perceptual contrast even for small text, but
 * I don't want toggling the theme to impact anything besides color so
 * I set the weight here. */
kbd {
	font-weight: bold;
}

/* narrow screens: remove unused figure margins
 * figure captions shouldn't look like regular paragraphs; there should
 * be some extra space.
 * This does not hold true for figures in somewhat distinct sections; the
 * section should instead get the spacing. A section that constitutes a
 * separate schema.org object would qualify. */
section[itemprop="mentions"],
figure {
	margin: 1.5em 0;
}

section[itemprop="mentions"] > figure {
	margin: 0;
}

section[itemtype="https://schema.org/ImageObject"] figcaption,
figure[itemtype="https://schema.org/ImageObject"] figcaption,
div[itemprop="articleBody"] > figure:not([itemtype="https://schema.org/ImageObject"]) {
	contain: content;
}

/* browsers make monospace small and unreadable for some dumb legacy
 * reason and this somehow fixes that without overriding the user's
 * font size preferences. */
code,
kbd,
pre, /* Needed for ancient browsers */
samp {
	font-family: monospace, monospace;
}

/* Narrow screens: long words can cause content to flow out of the
 * viewport, triggering horizontal scrolling. Allow breaking words in
 * content I don't control (comments, names). For content I do control,
 * I just add soft hyphens to the HTML. */
li[itemprop="comment"],
:not(pre) > code,
:not(pre) > samp,
span[itemtype="https://schema.org/Person"] {
	overflow-wrap: break-word;
}

/* Narrow screens: allow horizontal scroll in a pre block. */
pre {
	overflow: auto;
	padding: .5em;
}

/* Distinguish images from the background in case their color is
 * too similar to the page background color. Also put a border around
 * <pre> and <code> to distinguish them in ways besides font-family.
 * This is Technique C25 of SC 1.4.8 */
img,
pre {
	border: 1px solid;
}

/* A black border is too harsh; the extra visual noise is distracting
 * to users with eye-tracking or ADHD. Only special items like headings
 * should draw gaze. */
:not(pre) > code,
:not(pre) > samp {
	border: 1px solid #999;

	/* borders shouldn't touch text */
	padding: 0 0.125em;
}

/* center standalone images; same justification as
 * for centering the body contents. Also makes images easier to see
 * for people holding a device with one hand. */
picture > img {
	display: block;
	height: auto;
	margin: auto;
	max-width: 100%;
}

/* Some images look blurry when scaled; this makes them easier to
 * read. */
.pix {
	image-rendering: pixelated;
}

/* WCAG Technique C25: use borders to separate sections.
 * Also use "content-visibility: auto" to improve performance by
 * reducing the number of DOM nodes rendered at once. */
footer,
section[aria-labelledby="webmentions"] {
	border-top: 1px solid;
	content-visibility: auto;
}


/* Some browser focus indicators are inaccessible; override them with
 * something more visible. See WCAG 2.x SC 2.4.12. I also tried to
 * match browser behavior; mainstream browsers use :focus-visible
 * instead of focus but older/simpler browsers only support :focus.
 * I borrowed these directives from
 * https://www.tempertemper.net/blog/refining-focus-styles-with-focus-visible
 * To my knowledge: <a>, <summary>, and <pre tabindex=0> are the only
 * focusable elements.
 * */

a:focus,
summary:focus,
pre[tabindex]:focus {
	outline: 3px solid;
}

/* Remove :focus styling for browsers that do support :focus-visible */
@supports selector(:focus-visible) {
	a:focus:not(:focus-visible),
	summary:focus:not(:focus-visible),
	pre[tabindex]:focus:not(:focus-visible) {
		outline: none;
	}
}

/* Todo:
 * - Some browsers don't scale SVGs properly; the img container
 *   dimensions crop the image rather than scale it. Investigate
 *   if this only applies to Internet Explorer or if it applies to
 *   other uncommon browsers too. If any non-IE browsers do this and/or
 *   if the spec allows this behavior, try to correct it here.
 * - Wait till Webkit fixes its broken-ass default dark stylesheet
 *   then consider trimming the dark stylesheet I provide.
 * */