@layer tokens, base, header, entries, prose, footer, responsive;

@layer tokens {
	/* Every colour is a light-dark() pair resolved by the element's
	color-scheme: the OS preference by default, a stored choice via
	data-theme, and always dark inside the hero (see hero.css). */
	:root {
		color-scheme: light dark;

		--color-bg: light-dark(#f5f5f5, #121212);
		--color-surface: light-dark(#ffffff, #1c1c1c);
		--color-text: light-dark(#161616, #ececec);
		--color-muted: light-dark(#4d4d4d, #a8a8a8);
		--color-border: light-dark(#cfcfcf, #2e2e2e);
		--color-accent: light-dark(#1a7359, #93b8a9);
		--color-wash-1: light-dark(#ecf1e6, #2a332c);
		--color-wash-2: light-dark(#f1f1f1, #2e2e2e);
		--color-wash-3: light-dark(#e0e8ed, #22303a);

		/* The two semantic graphic colours diagrams draw with (X vs O,
		set P vs set Q); everything else in a diagram reuses the tokens
		above. Non-text contrast (3:1) on bg and surface is tested. */
		--color-diagram-x: light-dark(#0c7485, #54d4e8);
		--color-diagram-o: light-dark(#b85a08, #ffad66);

		--content-width: 68rem;
		--prose-width: 65ch;

		--font-ui:
			-apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto,
			"Helvetica Neue", Arial, sans-serif;
		--font-reading: Georgia, "Times New Roman", serif;
		--font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
	}

	:root[data-theme="light"] {
		color-scheme: light;
	}

	:root[data-theme="dark"] {
		color-scheme: dark;
	}
}

@layer base {
	*,
	*::before,
	*::after {
		box-sizing: border-box;
	}

	/* Full-height column so the footer sits at the bottom of the viewport
	on short pages instead of wherever the content happens to end. */
	body {
		display: flex;
		flex-direction: column;
		min-height: 100svh;
		margin: 0;
		background: var(--color-bg);
		color: var(--color-text);
		font-family: var(--font-ui);
		line-height: 1.6;
	}

	main {
		flex: 1;
	}

	.wrap {
		width: min(calc(100% - 2 * clamp(1rem, 4vw, 2.5rem)), var(--content-width));
		margin-inline: auto;
	}

	a {
		color: var(--color-accent);
		text-underline-offset: 0.15em;
	}

	@media (hover: hover) {
		a:hover {
			text-decoration-thickness: 2px;
		}
	}

	:focus-visible {
		outline: 2px solid var(--color-accent);
		outline-offset: 3px;
	}

	/* Off-canvas until a keyboard user tabs to it, then pinned top-left
	above the header. */
	.skip-link {
		position: absolute;
		top: 0.5rem;
		left: 0.5rem;
		z-index: 10;
		padding: 0.5rem 0.9rem;
		border-radius: 0.5rem;
		background: var(--color-surface);
		color: var(--color-text);
		transform: translateY(-200%);
	}

	.skip-link:focus-visible {
		transform: none;
	}
}

@layer entries {
	.recent {
		padding-block: clamp(3rem, 7svh, 5rem);
	}

	.recent + .recent {
		padding-block-start: 0;
	}

	.index-page {
		padding-block: clamp(2rem, 5svh, 3.5rem);
	}

	.recent h2,
	.wrap > h1 {
		margin: 0 0 0.5rem;
		font-family: var(--font-reading);
		font-weight: 400;
		font-size: clamp(1.5rem, 1.3rem + 1vw, 1.9rem);
	}

	.index-count {
		margin: 0 0 1.5rem;
		color: var(--color-muted);
		font-size: 0.9rem;
		letter-spacing: 0.035em;
	}

	.more-link {
		margin: 1.5rem 0 0;
		text-align: right;
	}

	.card-grid {
		margin: 0;
		padding: 0;
		list-style: none;
		display: grid;
		grid-template-columns: 1fr;
		gap: 1.5rem;
	}

	.card-grid > li {
		display: flex;
		min-width: 0;
	}

	.card {
		position: relative;
		display: flex;
		flex-direction: column;
		flex: 1;
		width: 100%;
		overflow: clip;
		border: 1px solid var(--color-border);
		border-radius: 0.75rem;
		background: var(--color-surface);
		transition:
			transform 160ms ease,
			border-color 160ms ease,
			box-shadow 160ms ease;
	}

	@media (hover: hover) {
		.card:hover {
			transform: translateY(-2px);
			border-color: var(--color-muted);
			box-shadow: 0 12px 32px rgb(0 0 0 / 0.08);
		}
	}

	.card:has(.card-title a:focus-visible) {
		outline: 2px solid var(--color-accent);
		outline-offset: 3px;
	}

	.card:has(.card-title a:active) {
		border-color: var(--color-muted);
	}

	.card-media {
		position: relative;
		aspect-ratio: 16 / 9;
		overflow: hidden;
		background: var(--color-wash-1);
	}

	.card-media img {
		display: block;
		width: 100%;
		height: 100%;
		object-fit: cover;
	}

	/* Preview-only: drafts are never built for the published site. */
	.card-draft {
		border-style: dashed;
	}

	.draft-badge {
		position: absolute;
		top: 0.6rem;
		left: 0.6rem;
		z-index: 1;
		padding: 0.15rem 0.6rem;
		border: 1px solid var(--color-accent);
		border-radius: 999px;
		background: color-mix(in srgb, var(--color-surface) 85%, transparent);
		backdrop-filter: blur(4px);
		color: var(--color-accent);
		font-family: var(--font-ui);
		font-size: 0.7rem;
		letter-spacing: 0.08em;
		text-transform: uppercase;
	}

	.card-body {
		display: flex;
		flex-direction: column;
		gap: 0.6rem;
		flex: 1;
		padding: 1.25rem 1.25rem 1.1rem;
	}

	.card-title {
		margin: 0;
		font-family: var(--font-reading);
		font-weight: 400;
		font-size: 1.35rem;
		line-height: 1.3;
		min-height: 2.6em;
		display: -webkit-box;
		-webkit-line-clamp: 2;
		-webkit-box-orient: vertical;
		overflow: hidden;
	}

	.card-title a {
		color: var(--color-text);
		text-decoration: none;
	}

	@media (hover: hover) {
		.card-title a:hover {
			text-decoration: underline;
			text-underline-offset: 0.2em;
		}
	}

	.card-title a::after {
		content: "";
		position: absolute;
		inset: 0;
	}

	.entry-desc {
		margin: 0;
		min-height: 3.2em;
		color: var(--color-muted);
		display: -webkit-box;
		-webkit-line-clamp: 3;
		-webkit-box-orient: vertical;
		overflow: hidden;
	}

	.entry-meta {
		display: flex;
		flex-direction: column;
		gap: 0.5rem;
		margin: 0;
		padding-top: 0.75rem;
		color: var(--color-muted);
		font-size: 0.8rem;
		letter-spacing: 0.035em;
	}

	.entry-topics {
		display: flex;
		flex-wrap: wrap;
		gap: 0.4rem;
	}

	.entry-topics a,
	.entry-topics span {
		position: relative;
		z-index: 1;
		border: 1px solid var(--color-border);
		border-radius: 999px;
		padding: 0.1rem 0.6rem;
		color: var(--color-muted);
		text-decoration: none;
		font-size: 0.75rem;
	}

	@media (hover: hover) {
		.entry-topics a:hover {
			color: var(--color-text);
			border-color: var(--color-muted);
		}
	}
}

@layer footer {
	.site-footer {
		border-top: 1px solid var(--color-border);
		color: var(--color-muted);
		font-size: 0.9rem;
	}

	.footer-inner {
		display: flex;
		flex-wrap: wrap;
		justify-content: space-between;
		gap: 0.5rem 1.5rem;
		padding-block: 1.5rem 2rem;
	}

	.site-footer p {
		margin: 0;
	}

	.footer-link {
		display: inline-flex;
		align-items: center;
		gap: 0.4rem;
		color: var(--color-muted);
		text-decoration: none;
	}

	.footer-icon {
		width: 1.1rem;
		height: 1.1rem;
	}

	@media (hover: hover) {
		.footer-link:hover {
			color: var(--color-text);
			text-decoration: underline;
		}
	}
}

@layer responsive {
	@media (min-width: 42rem) {
		.card-grid {
			grid-template-columns: repeat(2, 1fr);
		}
	}

	@media (prefers-reduced-motion: reduce) {
		.card {
			transition: none;
		}

		@media (hover: hover) {
			.card:hover {
				transform: none;
				box-shadow: none;
			}
		}
	}
}