/* =========================================================================
   Single-post prev/next nav — rendered above the back-link on every
   single-{persona}.php template. Siblings stay inside the same
   id30_collection (publication ↔ publication, lab ↔ lab, blog ↔ blog).
   ========================================================================= */

.id30-post-nav {
	display: grid;
	grid-template-columns: 1fr;
	gap: 24px;
	margin-top: clamp(48px, 6vw, 80px);
	padding-top: 32px;
	border-top: 1px solid var(--color-line);
}

@media (min-width: 720px) {
	.id30-post-nav {
		grid-template-columns: 1fr 1fr;
		gap: 32px;
	}
}

.id30-post-nav__cell {
	display: flex;
	flex-direction: column;
	gap: 10px;
	padding: 18px 0;
	color: var(--color-ink);
	text-decoration: none;
	min-width: 0;
}

.id30-post-nav__cell--next {
	text-align: right;
	align-items: flex-end;
}

/* Empty cell only takes a column at >=720px so the present cell stays
   anchored to its side; below the breakpoint we collapse it. */
.id30-post-nav__cell--empty { display: none; }
@media (min-width: 720px) {
	.id30-post-nav__cell--empty { display: block; }
}

.id30-post-nav__eyebrow {
	display: inline-flex;
	align-items: center;
	gap: 8px;
	font-family: var(--font-mono);
	font-size: 11px;
	letter-spacing: 0.3em;
	text-transform: uppercase;
	color: var(--color-ember);
}

.id30-post-nav__title {
	font-family: var(--font-title);
	font-weight: 400;
	font-size: clamp(1.02rem, 1.6vw, 1.18rem);
	line-height: 1.32;
	letter-spacing: -0.005em;
	color: var(--color-ink);
	transition: color 180ms var(--ease-spring);
	max-width: 36ch;
}

.id30-post-nav__cell:hover .id30-post-nav__title { color: var(--color-deep); }

.id30-post-nav__cell svg {
	color: var(--color-ember);
	transition: transform 200ms var(--ease-spring);
}

.id30-post-nav__cell--prev:hover .id30-post-nav__eyebrow svg { transform: translateX(-2px); }
.id30-post-nav__cell--next:hover .id30-post-nav__eyebrow svg { transform: translateX(2px); }

/* Blog persona uses a 64ch reading column — keep nav inside it. */
.id30-post--blog .id30-post-nav { max-width: 64ch; }