/* BasaltUSA navigation extension: preserve the editorial geology aesthetic while making every existing page reachable and easy to return from. */
:root {
  --ink: #1b1d1f;
  --ink-2: #4a4f55;
  --muted: #6b7178;
  --line: #d9dcdf;
  --bg: #fbfaf7;
  --card: #ffffff;
  --basalt: #2b2f33;   /* basalt grey-black */
  --basalt-2: #3d4348;
  --lava: #b3411f;     /* accent: cooled-lava rust */
  --lava-2: #8f321a;
  --olivine: #5f7f3a;  /* secondary accent */
  --tint: #eef0f1;
  --max: 1100px;
  --radius: 10px;
  font-size: 17px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font-family: Georgia, "Times New Roman", serif; line-height: 1.6;
}
h1, h2, h3, h4, .brand-name, nav, .btn, th, .kicker, .stat b, .card h3, .tag {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
h1 { font-size: clamp(1.9rem, 4vw, 2.7rem); line-height: 1.15; margin: 0 0 .5rem; letter-spacing: -.01em; }
h2 { font-size: clamp(1.4rem, 2.6vw, 1.8rem); margin: 2.4rem 0 .8rem; line-height: 1.2; }
h3 { font-size: 1.15rem; margin: 1.6rem 0 .5rem; }
p { margin: 0 0 1rem; }
a { color: var(--lava-2); }
a:hover { color: var(--lava); }
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 1.2rem; }
main.wrap { padding-top: 1.2rem; padding-bottom: 3rem; }
.muted { color: var(--muted); }
.small { font-size: .88rem; }
.lede { font-size: 1.18rem; color: var(--ink-2); max-width: 62ch; }
.kicker { text-transform: uppercase; letter-spacing: .12em; font-size: .75rem; color: var(--lava); font-weight: 700; margin: 0 0 .4rem; }
.skip { position: absolute; left: -999px; top: 0; background: var(--lava); color: #fff; padding: .5rem 1rem; }
.skip:focus { left: .5rem; z-index: 99; }

/* header */
.site-header { background: var(--basalt); color: #fff; border-bottom: 4px solid var(--lava); }
.header-inner { display: flex; align-items: center; justify-content: space-between; gap: .6rem; padding-top: .8rem; padding-bottom: .8rem; }
.brand { display: flex; align-items: center; gap: .6rem; color: #fff; text-decoration: none; }
.brand-mark { width: 26px; height: 26px; background: linear-gradient(135deg, var(--lava) 0 45%, #f2a97d 45% 55%, var(--basalt-2) 55%); clip-path: polygon(50% 0, 100% 25%, 100% 75%, 50% 100%, 0 75%, 0 25%); }
.brand-name { font-weight: 800; font-size: 1.25rem; letter-spacing: -.02em; margin: 0; }
.brand-name em { font-style: normal; color: #f2a97d; }
.site-nav ul { list-style: none; margin: 0; padding: 0; display: flex; gap: .1rem; flex-wrap: nowrap; }
.site-nav a { color: #e9ebed; text-decoration: none; padding: .4rem .32rem; border-radius: 6px; font-size: .8rem; font-weight: 600; }
.site-nav a:hover, .site-nav a[aria-current="page"] { background: rgba(255,255,255,.12); color: #fff; }
.all-pages-menu { position: relative; }
.all-pages-menu details { display: block; background: transparent; border: 0; border-radius: 0; margin: 0; padding: 0; }
.all-pages-menu summary { color: #e9ebed; cursor: pointer; list-style: none; padding: .4rem .32rem; border-radius: 6px; font-size: .8rem; font-weight: 600; white-space: nowrap; }
.all-pages-menu summary::-webkit-details-marker { display: none; }
.all-pages-menu summary::after { content: "▾"; font-size: .72em; margin-left: .35rem; }
.all-pages-menu details[open] > summary, .all-pages-menu summary:hover { background: rgba(255,255,255,.12); color: #fff; }
.all-pages-panel { position: absolute; right: 0; top: calc(100% + .55rem); width: min(760px, calc(100vw - 2rem)); max-height: min(70vh, 660px); overflow: auto; z-index: 30; padding: 1rem 1.1rem; background: #fff; color: var(--ink); border: 1px solid var(--line); border-top: 3px solid var(--lava); border-radius: 0 0 var(--radius) var(--radius); box-shadow: 0 16px 40px rgba(0,0,0,.25); }
.menu-heading { margin: .15rem 0 .4rem; color: var(--ink); font: 800 .78rem/1.2 system-ui, sans-serif; letter-spacing: .08em; text-transform: uppercase; }
.menu-heading + .menu-link-list { margin-bottom: 1rem; }
.menu-link-list { columns: 2; column-gap: 1.7rem; list-style: none; margin: 0; padding: 0; }
.menu-link-list li { break-inside: avoid; margin: 0 0 .35rem; }
.menu-link-list a { display: block; padding: .12rem 0; color: var(--lava-2); font: 600 .84rem/1.3 system-ui, sans-serif; text-decoration: none; }
.menu-link-list a:hover { color: var(--lava); text-decoration: underline; }
.nav-toggle { display: none; background: none; color: #fff; border: 1px solid rgba(255,255,255,.4); padding: .4rem .8rem; border-radius: 6px; }
@media (max-width: 960px) {
  .nav-toggle { display: inline-block; }
  .site-nav ul { display: none; flex-direction: column; position: absolute; right: 1rem; background: var(--basalt-2); padding: .6rem; border-radius: 8px; z-index: 20; }
  .site-nav ul.open { display: flex; }
  .all-pages-panel { position: static; width: min(100%, 650px); margin-top: .5rem; }
  .menu-link-list { columns: 1; }
}

/* breadcrumbs */
.crumbs ol { list-style: none; display: flex; flex-wrap: wrap; gap: .3rem; padding: .8rem 0 0; margin: 0; font-size: .85rem; color: var(--muted); }
.crumbs li + li::before { content: "›"; margin-right: .3rem; }
.crumbs a { color: var(--muted); }

/* hero */
.hero { background: linear-gradient(180deg, #fff 0%, var(--tint) 100%); border: 1px solid var(--line); border-radius: var(--radius); padding: 2rem 1.6rem; margin: 1rem 0 2rem; }
.hero .grid { display: grid; grid-template-columns: 1.4fr 1fr; gap: 2rem; align-items: center; }
@media (max-width: 760px) { .hero .grid { grid-template-columns: 1fr; } }
.btn { display: inline-block; background: var(--lava); color: #fff; text-decoration: none; padding: .7rem 1.1rem; border-radius: 8px; font-weight: 700; margin: .4rem .5rem .4rem 0; }
.btn.secondary { background: var(--basalt); }
.btn:hover { color: #fff; filter: brightness(1.08); }

/* stats */
.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: .8rem; margin: 1.2rem 0; }
.stat { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: .9rem 1rem; }
.stat b { display: block; font-size: 1.5rem; color: var(--basalt); line-height: 1.1; }
.stat span { font-size: .85rem; color: var(--muted); }

/* cards */
.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 1rem; margin: 1.2rem 0; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 1.1rem 1.2rem; display: flex; flex-direction: column; }
.card h3 { margin: .2rem 0 .4rem; font-size: 1.05rem; }
.card p { font-size: .95rem; color: var(--ink-2); margin-bottom: .6rem; }
.card a.more { margin-top: auto; font-weight: 700; text-decoration: none; font-size: .9rem; }
.tag { display: inline-block; font-size: .7rem; text-transform: uppercase; letter-spacing: .08em; font-weight: 700; padding: .15rem .5rem; border-radius: 999px; background: var(--tint); color: var(--ink-2); margin-bottom: .3rem; }
.tag.high { background: #f8e3d9; color: var(--lava-2); }
.tag.medium { background: #e9eee2; color: #4a642c; }
.tag.niche { background: #e6ecf3; color: #33506b; }

/* tables */
.table-wrap { overflow-x: auto; margin: 1rem 0 1.5rem; border: 1px solid var(--line); border-radius: var(--radius); background: var(--card); }
table { border-collapse: collapse; width: 100%; font-size: .93rem; }
th, td { text-align: left; padding: .6rem .8rem; border-bottom: 1px solid var(--line); vertical-align: top; }
th { background: var(--tint); font-size: .8rem; text-transform: uppercase; letter-spacing: .06em; }
tr:last-child td { border-bottom: 0; }

/* callouts */
.callout { border-left: 5px solid var(--lava); background: #fff; border-radius: 0 var(--radius) var(--radius) 0; padding: .9rem 1.1rem; margin: 1.2rem 0; }
.callout.green { border-color: var(--olivine); }
.callout.grey { border-color: var(--basalt-2); }
.callout p:last-child { margin-bottom: 0; }

/* spec sheet */
.spec { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: .8rem; margin: 1rem 0 1.5rem; }
.spec div { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: .8rem 1rem; font-size: .93rem; }
.spec div b { display: block; font-family: system-ui, sans-serif; font-size: .78rem; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); margin-bottom: .2rem; }

/* toc */
.toc { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: .9rem 1.1rem; margin: 1rem 0 1.5rem; font-size: .92rem; }
.toc ol { margin: .3rem 0 0; padding-left: 1.2rem; columns: 2; column-gap: 2rem; }
@media (max-width: 640px) { .toc ol { columns: 1; } }

/* faq */
details { border: 1px solid var(--line); background: var(--card); border-radius: 8px; padding: .6rem 1rem; margin: .5rem 0; }
summary { cursor: pointer; font-weight: 700; font-family: system-ui, sans-serif; }
details p { margin: .6rem 0 .2rem; }

/* footer */
.site-footer { background: var(--basalt); color: #d9dcdf; margin-top: 2rem; padding: 2rem 0 1rem; }
.footer-inner { display: grid; grid-template-columns: 1.5fr 1fr; gap: 2rem; }
@media (max-width: 700px) { .footer-inner { grid-template-columns: 1fr; } }
.site-footer .brand-name { color: #fff; }
.site-footer .muted { color: #a9afb5; }
.footer-links { list-style: none; padding: 0; margin: 0; columns: 2; }
.footer-links a { color: #e9ebed; text-decoration: none; font-size: .92rem; line-height: 1.9; }
.footer-page-index { border-top: 1px solid rgba(255,255,255,.18); margin-top: 1.6rem; padding-top: 1.5rem; }
.footer-page-index h2, .footer-page-index h3 { color: #fff; }
.footer-page-index h2 { margin: .1rem 0 1.1rem; font-size: 1.2rem; }
.footer-page-index h3 { margin: 0 0 .55rem; font-size: .88rem; letter-spacing: .04em; text-transform: uppercase; }
.footer-index-sections { display: grid; grid-template-columns: minmax(155px, .8fr) minmax(180px, 1fr) minmax(0, 2.1fr); gap: 1.6rem 2.1rem; }
.footer-page-list { columns: 2; column-gap: 1.6rem; list-style: none; margin: 0; padding: 0; }
.footer-use-index .footer-page-list { columns: 3; }
.footer-page-list li { break-inside: avoid; margin: 0 0 .34rem; }
.footer-page-list a { color: #e9ebed; font: 600 .8rem/1.35 system-ui, sans-serif; text-decoration: none; }
.footer-page-list a:hover { color: #fff; text-decoration: underline; }
.copyright { padding-top: 1.2rem; }
.site-footer .footer-links { columns: 1; }

/* Human-readable sitemap: the complete index has moved out of the footer into grouped, responsive text-link sections. */
.sitemap-groups { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1rem; margin: 2rem 0; }
.sitemap-group { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 1.2rem 1.3rem; }
.sitemap-group h2 { margin: .1rem 0 .85rem; font-size: 1.3rem; }
.sitemap-use-group { grid-column: 1 / -1; }
.sitemap-links { columns: 2; column-gap: 2rem; list-style: none; margin: 0; padding: 0; }
.sitemap-use-group .sitemap-links { columns: 3; }
.sitemap-links li { break-inside: avoid; margin: 0 0 .42rem; }
.sitemap-links a { font-size: .92rem; }
@media (max-width: 760px) {
  .sitemap-groups { grid-template-columns: 1fr; }
  .sitemap-use-group { grid-column: auto; }
  .sitemap-links, .sitemap-use-group .sitemap-links { columns: 1; }
}
.back-to-top { position: fixed; right: 1.15rem; bottom: 1.15rem; z-index: 25; border: 0; border-radius: 999px; background: var(--lava); color: #fff; box-shadow: 0 5px 16px rgba(0,0,0,.28); cursor: pointer; font: 800 .76rem/1 system-ui, sans-serif; letter-spacing: .04em; opacity: 0; padding: .75rem .72rem; pointer-events: none; transform: translateY(.7rem); transition: opacity .18s ease-out, transform .18s ease-out, background-color .18s ease-out; }
.back-to-top:hover { background: var(--lava-2); }
.back-to-top:focus-visible { outline: 3px solid #f2a97d; outline-offset: 3px; }
.back-to-top.is-visible { opacity: 1; pointer-events: auto; transform: translateY(0); }
@media (max-width: 700px) {
  .footer-index-sections { grid-template-columns: 1fr; }
  .footer-use-index .footer-page-list, .footer-page-list { columns: 1; }
  .back-to-top { right: .8rem; bottom: .8rem; }
}
.prose { max-width: 72ch; }
.prose ul, .prose ol { padding-left: 1.3rem; }
figure { margin: 1.2rem 0; }
figcaption { font-size: .85rem; color: var(--muted); }
.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; }
@media (max-width: 720px) { .two-col { grid-template-columns: 1fr; } }

/* ---------- visuals: charts, diagrams, photos, hero art ---------- */
:root { --c1: #c2410c; --c1-light: #e4936b; --c2: #1f6fb0; --c3: #c9a227; --c4: #6d4fb3; --cbar: #9aa1a8; }
.chart { margin: 1.6rem 0 2rem; background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 1rem 1.1rem .8rem; }
.chart figcaption { display: flex; flex-direction: column; gap: .15rem; margin-bottom: .6rem; }
.chart-title { font-family: system-ui, sans-serif; font-weight: 700; font-size: 1.05rem; color: var(--ink); }
.chart-sub { font-size: .88rem; color: var(--muted); }
.chart-source { font-size: .78rem; color: var(--muted); margin: .5rem 0 0; }
.chart-body { overflow-x: auto; }
.svgchart { width: 100%; height: auto; display: block; font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; }
.svgchart .lbl { font-size: 13px; fill: var(--ink-2); }
.svgchart .val { font-size: 13px; fill: var(--ink-2); }
.svgchart .strong { font-weight: 700; fill: var(--ink); }
.svgchart .tick { font-size: 11px; fill: var(--muted); }
.svgchart .grid { stroke: var(--line); stroke-width: 1; }
.svgchart .limit { stroke: var(--ink-2); stroke-width: 1.5; stroke-dasharray: 4 3; }
.svgchart .link { fill: var(--lava-2); text-decoration: underline; cursor: pointer; }
.svgchart .bar-row rect { transition: opacity .15s; }
.svgchart:hover .bar-row rect { opacity: .55; }
.svgchart .bar-row:hover rect { opacity: 1; stroke: var(--ink); stroke-width: 1.5; }
.legend { list-style: none; display: flex; flex-wrap: wrap; gap: .4rem 1.1rem; padding: 0; margin: 0 0 .6rem; font-family: system-ui, sans-serif; font-size: .82rem; color: var(--ink-2); }
.legend i { display: inline-block; width: 12px; height: 12px; border-radius: 3px; margin-right: .4rem; vertical-align: -1px; }
.chart-table { border: 0; background: transparent; padding: 0; margin: .4rem 0 0; }
.chart-table summary { font-size: .82rem; color: var(--muted); font-weight: 600; }
.chart-table .table-wrap { margin: .5rem 0 0; }
.tilemap .tile rect { stroke: #fff; stroke-width: 2; }
.tilemap .tile.major rect { fill: var(--c1); }
.tilemap .tile.sig rect { fill: var(--c1-light); }
.tilemap .tile.minor rect { fill: var(--cbar); }
.tilemap .tile.none rect { fill: var(--tint); }
.tilemap .tile text { font-size: 13px; font-weight: 700; fill: #fff; pointer-events: none; }
.tilemap .tile.none text { fill: var(--muted); font-weight: 600; }
.tilemap .tile:hover rect { stroke: var(--ink); }
.diagram .svgchart { border-radius: 8px; }

/* photos */
.photo { margin: 1.4rem 0; }
.photo img, .photo-ph { width: 100%; border-radius: var(--radius); object-fit: cover; display: block; }
.photo-ph { background: repeating-linear-gradient(135deg, #2b2f33 0 14px, #34393e 14px 28px); color: #e9ebed; display: flex; flex-direction: column; justify-content: flex-end; padding: 1rem 1.2rem; box-sizing: border-box; }
.ph-tag { font-family: system-ui, sans-serif; font-size: .72rem; letter-spacing: .08em; text-transform: uppercase; color: #f2a97d; margin-bottom: .3rem; }
.ph-brief { font-size: .95rem; max-width: 60ch; text-shadow: 0 1px 2px #000; }
.photo figcaption { font-size: .85rem; color: var(--muted); margin-top: .4rem; }
.photo .credit { color: var(--muted); font-style: italic; }
.photo.wide { grid-column: 1 / -1; }
.photo-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 1rem; }
.photo-grid .photo { margin: 0; }

/* hero art banner */
.banner { position: relative; border-radius: var(--radius); overflow: hidden; margin: 1rem 0 1.6rem; min-height: 200px; display: grid; align-items: end; background: #24282c; }
.banner .hero-art { position: absolute; inset: 0; width: 100%; height: 100%; }
.banner .banner-text { position: relative; padding: 2rem 1.6rem 1.4rem; color: #fff; }
.banner .banner-text h1 { color: #fff; margin: 0 0 .3rem; text-shadow: 0 2px 8px rgba(0,0,0,.5); }
.banner .banner-text .kicker { color: #f2a97d; }
.banner .banner-text .lede { color: #e9ebed; text-shadow: 0 1px 4px rgba(0,0,0,.6); margin: 0; }
.hero.dark { background: #24282c; border: 0; position: relative; overflow: hidden; color: #fff; }
.hero.dark .hero-art { position: absolute; inset: 0; width: 100%; height: 100%; }
.hero.dark .grid { position: relative; }
.hero.dark h1, .hero.dark .lede { color: #fff; text-shadow: 0 2px 8px rgba(0,0,0,.55); }
.hero.dark .lede { color: #e9ebed; }
.hero.dark .kicker { color: #f2a97d; }
.hero.dark .stat { background: rgba(255,255,255,.94); }