/* ==========================================================================
   BG7BAG Core — main.css
   Wikipedia-inspired, mobile-first reading styles for bg7bag.com rebuild.

   Rules of this file
   -------------------
   1. Exactly ONE stylesheet owns reading typography. Nothing else on the
      site may set body/h1-h6/p/a sizes — page templates have no <style>.
   2. NO !important anywhere. Specificity is kept deliberately low
      (single class or element+class) so nothing needs to fight it.
   3. Mobile-first: base rules are for the phone; @media (min-width: …)
      only *adds* desktop affordances (sidebar, sticky TOC).
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. Tokens
   -------------------------------------------------------------------------- */

:root {
	--bhi-font: Roboto, "Noto Sans SC", -apple-system, BlinkMacSystemFont,
		"Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
		Arial, sans-serif;
	--bhi-ink: #212121;
	--bhi-ink-soft: #5f6368;
	--bhi-ink-faint: #9aa0a6;
	--bhi-link: #0000ee;
	--bhi-link-visited: #551a8b;
	--bhi-border: #dadce0;
	--bhi-surface: #f8f9fa;
	--bhi-measure: 42rem; /* ~672px at 16px — Wikipedia-like line length */
	--bhi-radius: 8px;
	--bhi-tap: 48px; /* minimum touch target */
}

/* --------------------------------------------------------------------------
   2. Base
   -------------------------------------------------------------------------- */

html body {
	font-family: var(--bhi-font);
	font-size: 16px;
	line-height: 1.5;
	color: var(--bhi-ink);
	background: #fff;
	-webkit-text-size-adjust: 100%;
}

html body p {
	margin: 0 0 1em;
	max-width: var(--bhi-measure);
}

/* Headings — Google Material scale, weight 500, Wikipedia-like rhythm. */
html body h1,
html body h2,
html body h3,
html body h4,
html body h5,
html body h6 {
	font-weight: 500;
	line-height: 1.25;
	margin: 1.5em 0 0.5em;
	max-width: var(--bhi-measure);
	text-wrap: balance;
}

html body h1 { font-size: 2rem; }      /* 32px */
html body h2 {
	font-size: 1.5rem;                 /* 24px */
	padding-bottom: 0.25em;
	border-bottom: 1px solid var(--bhi-border);
}
html body h3 { font-size: 1.25rem; }   /* 20px */
html body h4 { font-size: 1.125rem; }  /* 18px */
html body h5 { font-size: 1rem; }      /* 16px */
html body h6 {
	font-size: 0.875rem;              /* 14px */
	color: var(--bhi-ink-soft);
}

/* Anchor affordance: hover a heading to reveal its permalink (¶). */
html body .bhi-content h2 .bhi-anchor,
html body .bhi-content h3 .bhi-anchor {
	margin-left: 0.4em;
	font-size: 0.7em;
	color: var(--bhi-ink-faint);
	text-decoration: none;
	opacity: 0;
}
html body .bhi-content h2:hover .bhi-anchor,
html body .bhi-content h3:hover .bhi-anchor {
	opacity: 1;
}

/* --------------------------------------------------------------------------
   3. Links — content links only. Chrome (logo, top nav, buttons) is
   excluded by scoping: these rules live under .bhi-content.
   -------------------------------------------------------------------------- */

html body .bhi-content a {
	color: var(--bhi-link);
	text-decoration: none;
}
html body .bhi-content a:visited {
	color: var(--bhi-link-visited);
}
html body .bhi-content a:hover,
html body .bhi-content a:focus-visible {
	text-decoration: underline;
}

/* --------------------------------------------------------------------------
   4. Prose elements
   -------------------------------------------------------------------------- */

html body .bhi-content ul,
html body .bhi-content ol {
	max-width: var(--bhi-measure);
	margin: 0 0 1em;
	padding-left: 1.5em;
}
html body .bhi-content li {
	margin-bottom: 0.25em;
}
html body .bhi-content blockquote {
	max-width: var(--bhi-measure);
	margin: 0 0 1em;
	padding: 0.5em 1em;
	border-left: 3px solid var(--bhi-border);
	color: var(--bhi-ink-soft);
}
html body .bhi-content code {
	font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
	font-size: 0.875em;
	background: var(--bhi-surface);
	padding: 0.1em 0.35em;
	border-radius: 4px;
}
html body .bhi-content pre {
	max-width: var(--bhi-measure);
	overflow-x: auto;
	background: var(--bhi-surface);
	border: 1px solid var(--bhi-border);
	border-radius: var(--bhi-radius);
	padding: 1em;
}
html body .bhi-content pre code {
	background: none;
	padding: 0;
}
html body .bhi-content table {
	border-collapse: collapse;
	margin: 0 0 1em;
	max-width: 100%;
	display: block;
	overflow-x: auto;
}
html body .bhi-content th,
html body .bhi-content td {
	border: 1px solid var(--bhi-border);
	padding: 0.5em 0.75em;
	text-align: left;
	font-size: 0.9375rem;
}
html body .bhi-content th {
	background: var(--bhi-surface);
	font-weight: 500;
}
html body .bhi-content img {
	max-width: 100%;
	height: auto;
	border-radius: 4px;
}
html body .bhi-content figure {
	margin: 0 0 1em;
	max-width: var(--bhi-measure);
}
html body .bhi-content figcaption {
	font-size: 0.875rem;
	color: var(--bhi-ink-soft);
	margin-top: 0.25em;
}

/* --------------------------------------------------------------------------
   5. Page shell — centered column, Wikipedia-like.
   -------------------------------------------------------------------------- */

.bhi-page {
	max-width: 72rem;
	margin: 0 auto;
	padding: 0 1rem;
}
.bhi-main {
	padding: 1rem 0 3rem;
}
.bhi-content > *:first-child {
	margin-top: 0;
}

/* Two-column (content + sticky sidebar) on desktop only. */
@media (min-width: 64rem) {
	.bhi-layout {
		display: grid;
		grid-template-columns: minmax(0, 1fr) 18.75rem;
		gap: 2rem;
		align-items: start;
	}
	.bhi-sidebar {
		position: sticky;
		top: 1rem;
	}
}
@media (max-width: 63.9375rem) {
	.bhi-sidebar {
		margin-top: 2rem;
		border-top: 1px solid var(--bhi-border);
		padding-top: 1rem;
	}
}

/* --------------------------------------------------------------------------
   6. Breadcrumb
   -------------------------------------------------------------------------- */

.bhi-breadcrumb {
	font-size: 0.8125rem;
	color: var(--bhi-ink-soft);
	margin-bottom: 0.75rem;
}
.bhi-breadcrumb ol {
	list-style: none;
	display: flex;
	flex-wrap: wrap;
	gap: 0.25em;
	margin: 0;
	padding: 0;
}
.bhi-breadcrumb li + li::before {
	content: "›";
	margin-right: 0.25em;
	color: var(--bhi-ink-faint);
}
.bhi-breadcrumb a {
	color: var(--bhi-ink-soft);
	text-decoration: none;
}
.bhi-breadcrumb a:hover {
	text-decoration: underline;
}

/* --------------------------------------------------------------------------
   7. Table of contents — <details> on mobile, static card on desktop.
   -------------------------------------------------------------------------- */

.bhi-toc {
	max-width: var(--bhi-measure);
	margin: 0 0 1.5em;
	border: 1px solid var(--bhi-border);
	border-radius: var(--bhi-radius);
	background: var(--bhi-surface);
	font-size: 0.9375rem;
}
.bhi-toc summary {
	padding: 0.75em 1em;
	font-weight: 500;
	cursor: pointer;
	min-height: var(--bhi-tap);
	display: flex;
	align-items: center;
	list-style: none;
}
.bhi-toc summary::-webkit-details-marker {
	display: none;
}
.bhi-toc summary::before {
	content: "▸";
	margin-right: 0.5em;
	color: var(--bhi-ink-soft);
}
.bhi-toc details[open] summary::before {
	content: "▾";
}
.bhi-toc__list {
	margin: 0;
	padding: 0 1em 1em 2.25em;
}
.bhi-toc__list li {
	margin-bottom: 0.25em;
}
.bhi-toc__list ol {
	margin-top: 0.25em;
	padding-left: 1.25em;
}
.bhi-toc__list a {
	color: var(--bhi-ink);
	text-decoration: none;
}
.bhi-toc__list a:hover {
	text-decoration: underline;
	color: var(--bhi-link);
}

/* --------------------------------------------------------------------------
   8. Prev / index / next bar
   -------------------------------------------------------------------------- */

.bhi-prevnext {
	display: grid;
	grid-template-columns: 1fr auto 1fr;
	gap: 0.5rem;
	align-items: center;
	max-width: var(--bhi-measure);
	margin: 2em 0;
	padding: 0.75em 0;
	border-top: 1px solid var(--bhi-border);
	border-bottom: 1px solid var(--bhi-border);
}
.bhi-prevnext__prev,
.bhi-prevnext__next,
.bhi-prevnext__index {
	display: inline-flex;
	align-items: center;
	min-height: var(--bhi-tap);
	padding: 0.5em 1em;
	border: 1px solid var(--bhi-border);
	border-radius: var(--bhi-radius);
	text-decoration: none;
	color: var(--bhi-ink);
	font-size: 0.9375rem;
	background: #fff;
}
.bhi-prevnext__prev:hover,
.bhi-prevnext__next:hover,
.bhi-prevnext__index:hover {
	background: var(--bhi-surface);
	text-decoration: none;
}
.bhi-prevnext__prev { justify-self: start; }
.bhi-prevnext__next { justify-self: end; }
.bhi-prevnext__index { justify-self: center; }
.bhi-prevnext__prev--disabled,
.bhi-prevnext__next--disabled {
	visibility: hidden;
}

/* --------------------------------------------------------------------------
   9. Chapter select (jump-to-chapter dropdown)
   -------------------------------------------------------------------------- */

.bhi-chapter-select {
	display: flex;
	align-items: center;
	gap: 0.5em;
	max-width: var(--bhi-measure);
	margin: 0 0 1em;
	font-size: 0.9375rem;
}
.bhi-chapter-select select {
	flex: 1;
	min-height: var(--bhi-tap);
	font-size: 1rem;
	font-family: inherit;
	border: 1px solid var(--bhi-border);
	border-radius: var(--bhi-radius);
	padding: 0.5em;
	background: #fff;
	color: var(--bhi-ink);
}

/* --------------------------------------------------------------------------
   10. Infobox (device manuals) — Wikipedia-style, right on desktop,
   stacked on mobile.
   -------------------------------------------------------------------------- */

.bhi-infobox {
	border: 1px solid var(--bhi-border);
	border-radius: var(--bhi-radius);
	background: var(--bhi-surface);
	font-size: 0.875rem;
	margin: 0 0 1.5em;
	overflow: hidden;
}
.bhi-infobox__title {
	font-weight: 500;
	font-size: 1rem;
	padding: 0.75em 1em;
	border-bottom: 1px solid var(--bhi-border);
	background: #fff;
}
.bhi-infobox table {
	width: 100%;
	border-collapse: collapse;
}
.bhi-infobox th,
.bhi-infobox td {
	padding: 0.5em 1em;
	border-bottom: 1px solid var(--bhi-border);
	vertical-align: top;
	text-align: left;
}
.bhi-infobox tr:last-child th,
.bhi-infobox tr:last-child td {
	border-bottom: none;
}
.bhi-infobox th {
	font-weight: 500;
	color: var(--bhi-ink-soft);
	width: 38%;
}
@media (min-width: 48rem) {
	.bhi-infobox {
		float: right;
		width: 19rem;
		margin: 0 0 1em 1.5em;
	}
}

/* --------------------------------------------------------------------------
   11. "See also" block
   -------------------------------------------------------------------------- */

.bhi-seealso {
	max-width: var(--bhi-measure);
	margin: 2em 0;
	padding: 1em;
	border: 1px solid var(--bhi-border);
	border-radius: var(--bhi-radius);
	background: var(--bhi-surface);
}
.bhi-seealso h2 {
	font-size: 1.125rem;
	margin: 0 0 0.5em;
	border: none;
	padding: 0;
}
.bhi-seealso ul {
	margin: 0;
	padding-left: 1.25em;
}

/* --------------------------------------------------------------------------
   12. Ad slots — labelled placeholders; ad tags wired in a later phase.
   Positioned per the approved spec, never inside a question list or a
   tool's task flow. Hidden in print.
   -------------------------------------------------------------------------- */

.bhi-ad {
	max-width: var(--bhi-measure);
	margin: 1.5em 0;
	min-height: 90px;
}
.bhi-ad--sidebar {
	max-width: none;
}
@media (min-width: 64rem) {
	.bhi-ad--sidebar {
		position: sticky;
		top: 1rem;
	}
}

/* --------------------------------------------------------------------------
   13. Question bank
   -------------------------------------------------------------------------- */

.bhi-question {
	max-width: var(--bhi-measure);
	border: 1px solid var(--bhi-border);
	border-radius: var(--bhi-radius);
	padding: 1em;
	margin: 0 0 1em;
	background: #fff;
}
.bhi-question__stem {
	font-weight: 500;
	margin: 0 0 0.75em;
}
.bhi-question__options {
	list-style: none;
	margin: 0;
	padding: 0;
	display: grid;
	gap: 0.5em;
}
.bhi-question__options button {
	width: 100%;
	text-align: left;
	min-height: var(--bhi-tap);
	padding: 0.75em 1em;
	font-size: 1rem;
	font-family: inherit;
	border: 1px solid var(--bhi-border);
	border-radius: var(--bhi-radius);
	background: #fff;
	color: var(--bhi-ink);
	cursor: pointer;
}
.bhi-question__options button:hover {
	background: var(--bhi-surface);
}
.bhi-question__options button[aria-pressed="true"] {
	border-color: var(--bhi-link);
	background: #eef3ff;
}
.bhi-question__feedback {
	margin-top: 0.75em;
	padding: 0.75em 1em;
	border-radius: var(--bhi-radius);
	font-size: 0.9375rem;
}
.bhi-question__feedback--correct {
	background: #e6f4ea;
	color: #137333;
}
.bhi-question__feedback--wrong {
	background: #fce8e6;
	color: #a50e0e;
}
.bhi-question__stem-cn {
	font-weight: 400;
	color: #5f6368;
	margin: -0.5em 0 0.75em;
}
.bhi-question__opt-cn {
	display: block;
	font-size: 0.875rem;
	color: #5f6368;
	margin-top: 0.25em;
}
.bhi-pagination {
	display: flex;
	justify-content: space-between;
	align-items: center;
	max-width: var(--bhi-measure);
	margin: 2em 0;
}
.bhi-pagination a,
.bhi-pagination span {
	min-height: var(--bhi-tap);
	display: inline-flex;
	align-items: center;
	padding: 0.5em 1em;
	border: 1px solid var(--bhi-border);
	border-radius: var(--bhi-radius);
	text-decoration: none;
	color: var(--bhi-ink);
}
.bhi-progress {
	max-width: var(--bhi-measure);
	font-size: 0.875rem;
	color: var(--bhi-ink-soft);
	margin-bottom: 1em;
}
.bhi-progress__bar {
	height: 6px;
	background: var(--bhi-border);
	border-radius: 3px;
	overflow: hidden;
	margin-top: 0.25em;
}
.bhi-progress__fill {
	height: 100%;
	background: var(--bhi-link);
	width: 0;
}

/* --------------------------------------------------------------------------
   14. FAQ (tools) — <details> accordions, 48px targets.
   -------------------------------------------------------------------------- */

.bhi-faq {
	max-width: var(--bhi-measure);
	margin: 2em 0;
}
.bhi-faq h2 {
	font-size: 1.25rem;
}
.bhi-faq details {
	border: 1px solid var(--bhi-border);
	border-radius: var(--bhi-radius);
	margin-bottom: 0.5em;
}
.bhi-faq summary {
	min-height: var(--bhi-tap);
	display: flex;
	align-items: center;
	padding: 0.75em 1em;
	font-weight: 500;
	cursor: pointer;
	list-style: none;
}
.bhi-faq summary::-webkit-details-marker {
	display: none;
}
.bhi-faq summary::before {
	content: "+";
	margin-right: 0.5em;
	color: var(--bhi-ink-soft);
	font-weight: 400;
}
.bhi-faq details[open] summary::before {
	content: "–";
}
.bhi-faq .bhi-faq__answer {
	padding: 0 1em 1em;
}
.bhi-faq .bhi-faq__answer p:last-child {
	margin-bottom: 0;
}

/* --------------------------------------------------------------------------
   15. Tool form controls — one shared size so every tool feels the same.
   (Phase 1 keeps specificity modest; per-tool inline styles are banned.)
   -------------------------------------------------------------------------- */

.bhi-tool input[type="number"],
.bhi-tool input[type="text"],
.bhi-tool input[type="date"],
.bhi-tool select {
	font-size: 1.125rem;
	min-height: 52px;
	padding: 0.75em;
	border: 1px solid var(--bhi-border);
	border-radius: var(--bhi-radius);
	font-family: inherit;
	width: 100%;
	box-sizing: border-box;
}
.bhi-tool button,
.bhi-tool input[type="submit"] {
	font-size: 1.125rem;
	font-weight: 700;
	min-height: 52px;
	padding: 0.75em 1.5em;
	border: none;
	border-radius: var(--bhi-radius);
	background: var(--bhi-link);
	color: #fff;
	cursor: pointer;
	font-family: inherit;
}
.bhi-tool button:hover {
	filter: brightness(0.92);
}
.bhi-tool label {
	display: block;
	font-weight: 500;
	margin-bottom: 0.25em;
}

/* --------------------------------------------------------------------------
   16. Sponsor banner slot (reserved; hidden until bg7bag_has_sponsor()).
   -------------------------------------------------------------------------- */

.bhi-sponsor {
	background: #fff8e1;
	border-bottom: 1px solid #ffe082;
	padding: 0.5em 1em;
	font-size: 0.875rem;
	text-align: center;
	position: relative;
}
.bhi-sponsor__close {
	position: absolute;
	right: 0.5em;
	top: 50%;
	transform: translateY(-50%);
	background: none;
	border: none;
	font-size: 1.25rem;
	cursor: pointer;
	min-width: var(--bhi-tap);
	min-height: var(--bhi-tap);
	color: var(--bhi-ink-soft);
}
.bhi-sponsor__tag {
	font-weight: 700;
	text-transform: uppercase;
	font-size: 0.75rem;
	letter-spacing: 0.05em;
	color: var(--bhi-ink-soft);
	margin-right: 0.5em;
}

/* Index / archive cards (theme index.php fallback loop). */
.bhi-card {
	max-width: var(--bhi-measure);
	margin-bottom: 2em;
}
.bhi-card__title {
	border: none;
	padding: 0;
}
.bhi-card__title a {
	color: var(--bhi-ink);
}
.bhi-card__meta {
	color: var(--bhi-ink-soft);
	font-size: 0.875rem;
}

/* Article meta line under the H1. */
.bhi-meta {
	color: var(--bhi-ink-soft);
	font-size: 0.875rem;
}

/* --------------------------------------------------------------------------
   17. Fullscreen toggle (map page) — keeps the header; the map element
   itself goes fullscreen instead of the page losing its navigation.
   -------------------------------------------------------------------------- */

.bhi-fullscreen-btn {
	min-height: var(--bhi-tap);
	min-width: var(--bhi-tap);
	border: 1px solid var(--bhi-border);
	border-radius: var(--bhi-radius);
	background: #fff;
	cursor: pointer;
	font-size: 1.125rem;
}

/* --------------------------------------------------------------------------
   18. Site chrome — header / nav / footer.
   The header is ALWAYS rendered (Wikipedia rule: no navigation-less
   pages). Fullscreen is a per-element toggle (see .bhi-fullscreen-btn),
   never a page without a header.
   -------------------------------------------------------------------------- */

.bhi-site-header {
	border-bottom: 1px solid var(--bhi-border);
	background: #fff;
}
.bhi-site-header__inner {
	max-width: 72rem;
	margin: 0 auto;
	padding: 0.5rem 1rem;
	display: flex;
	align-items: center;
	gap: 1rem;
	flex-wrap: wrap;
}
.bhi-site-logo {
	display: inline-flex;
	align-items: center;
	min-height: var(--bhi-tap);
	text-decoration: none;
	color: var(--bhi-ink);
	font-weight: 700;
	font-size: 1.125rem;
}
.bhi-site-logo img {
	height: 2rem;
	width: auto;
}
.bhi-site-search {
	flex: 1 1 12rem;
	max-width: 24rem;
	margin-left: auto;
}
.bhi-site-search form {
	display: flex;
}
.bhi-site-search input[type="search"] {
	flex: 1;
	min-height: var(--bhi-tap);
	border: 1px solid var(--bhi-border);
	border-radius: var(--bhi-radius) 0 0 var(--bhi-radius);
	padding: 0.5em 0.75em;
	font-size: 1rem;
	font-family: inherit;
}
.bhi-site-search button {
	min-height: var(--bhi-tap);
	min-width: var(--bhi-tap);
	border: 1px solid var(--bhi-border);
	border-left: none;
	border-radius: 0 var(--bhi-radius) var(--bhi-radius) 0;
	background: var(--bhi-surface);
	cursor: pointer;
	font-size: 1rem;
}
.bhi-nav {
	width: 100%;
}
.bhi-nav__list {
	list-style: none;
	display: flex;
	flex-wrap: wrap;
	gap: 0.25em 1em;
	margin: 0;
	padding: 0.5em 0 0;
	font-size: 0.9375rem;
}
.bhi-nav__list a {
	display: inline-flex;
	align-items: center;
	min-height: var(--bhi-tap);
	color: var(--bhi-ink);
	text-decoration: none;
	padding: 0 0.25em;
}
.bhi-nav__list a:hover {
	color: var(--bhi-link);
	text-decoration: underline;
}
/* Dropdowns (desktop): simple hover/focus reveal. */
.bhi-nav__list .sub-menu {
	display: none;
	position: absolute;
	background: #fff;
	border: 1px solid var(--bhi-border);
	border-radius: var(--bhi-radius);
	padding: 0.5em 0;
	list-style: none;
	margin: 0;
	min-width: 12rem;
	box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}
.bhi-nav__list li {
	position: relative;
}
.bhi-nav__list li:hover > .sub-menu,
.bhi-nav__list li:focus-within > .sub-menu {
	display: block;
}
.bhi-nav__list .sub-menu a {
	display: flex;
	padding: 0.5em 1em;
	white-space: nowrap;
}

.bhi-site-footer {
	border-top: 1px solid var(--bhi-border);
	margin-top: 3rem;
	padding: 1.5rem 1rem;
	font-size: 0.875rem;
	color: var(--bhi-ink-soft);
}
.bhi-site-footer__inner {
	max-width: 72rem;
	margin: 0 auto;
	display: flex;
	flex-wrap: wrap;
	gap: 0.5em 1.5em;
	align-items: center;
}
.bhi-site-footer a {
	color: var(--bhi-ink-soft);
	text-decoration: none;
}
.bhi-site-footer a:hover {
	text-decoration: underline;
}

/* --------------------------------------------------------------------------
   19. Print — Wikipedia-clean: content only.
   -------------------------------------------------------------------------- */

@media print {
	.bhi-site-header,
	.bhi-site-footer,
	.bhi-breadcrumb,
	.bhi-toc,
	.bhi-prevnext,
	.bhi-chapter-select,
	.bhi-ad,
	.bhi-sponsor,
	.bhi-progress,
	.bhi-pagination,
	.bhi-fullscreen-btn {
		display: none;
	}
	html body {
		font-size: 12pt;
		color: #000;
	}
	html body .bhi-content a {
		color: #000;
		text-decoration: none;
	}
	html body .bhi-content a[href^="http"]::after {
		content: " (" attr(href) ")";
		font-size: 0.8em;
		color: #555;
	}
	.bhi-page {
		max-width: none;
	}
	.bhi-infobox {
		float: none;
		width: auto;
	}
}