/* Chain Rattle — fairway green / sky / disc orange, mobile-first */
:root {
  --bg: #f3f8f4;
  --bg-card: #ffffff;
  --ink: #14261c;
  --muted: #4a6354;
  --accent: #e85d04;
  --accent-2: #f48c06;
  --fairway: #2d6a4f;
  --fairway-deep: #1b4332;
  --sky: #4cc9f0;
  --sky-soft: #caf0f8;
  --border: #c5d9cc;
  --header: #1b4332;
  --serif: "Source Serif 4", "Iowan Old Style", Georgia, "Times New Roman", serif;
  --sans: "IBM Plex Sans", "Segoe UI", system-ui, sans-serif;
  --max: 720px;
  --wide: 1000px;
  --radius: 10px;
  --shadow: 0 1px 2px rgba(27,67,50,.06), 0 8px 24px rgba(27,67,50,.08);
}
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--sans);
  color: var(--ink);
  background:
    radial-gradient(1200px 400px at 10% -10%, #d8f3dc 0%, transparent 55%),
    radial-gradient(900px 300px at 100% 0%, #caf0f8 0%, transparent 50%),
    var(--bg);
  line-height: 1.65;
  font-size: 1.05rem;
}
img { max-width: 100%; height: auto; }
a { color: var(--fairway); text-underline-offset: 2px; }
a:hover { color: var(--accent); }
.wrap { width: min(100% - 2rem, var(--wide)); margin-inline: auto; }
.wrap-narrow { width: min(100% - 2rem, var(--max)); margin-inline: auto; }

.site-header {
  background: var(--header);
  color: #f0fff4;
  position: sticky; top: 0; z-index: 40;
  border-bottom: 3px solid var(--accent);
}
.site-header .bar {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem; padding: .85rem 0; flex-wrap: wrap;
}
.brand {
  color: #f0fff4; text-decoration: none; font-weight: 700;
  letter-spacing: .02em; font-size: 1.05rem;
}
.brand span { color: #ffba08; font-weight: 600; }
.nav { display: flex; gap: .25rem .9rem; flex-wrap: wrap; }
.nav a {
  color: #d8f3dc; text-decoration: none; font-size: .95rem;
  padding: .25rem .1rem; border-bottom: 2px solid transparent;
}
.nav a:hover, .nav a[aria-current="page"] {
  color: #fff; border-bottom-color: #ffba08;
}

.hero {
  padding: 2.5rem 0 1.75rem;
  border-bottom: 1px solid var(--border);
}
.hero h1 {
  font-family: var(--serif);
  font-size: clamp(1.9rem, 4vw, 2.6rem);
  line-height: 1.2; margin: 0 0 .75rem; color: var(--header);
}
.hero .lede { color: var(--muted); font-size: 1.12rem; max-width: 42rem; margin: 0; }
.eyebrow {
  display: inline-block; font-size: .78rem; letter-spacing: .08em;
  text-transform: uppercase; color: var(--accent); font-weight: 700; margin-bottom: .5rem;
}

.grid {
  display: grid; gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  margin: 1.5rem 0;
}
.card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1.1rem 1.15rem; box-shadow: var(--shadow);
}
.card h3 { font-family: var(--serif); margin: 0 0 .4rem; font-size: 1.2rem; }
.card p { margin: 0; color: var(--muted); font-size: .98rem; }
.card a.card-link { text-decoration: none; color: inherit; display: block; }
.card a.card-link:hover h3 { color: var(--accent); }

main { padding: 1.75rem 0 3rem; }
article h1 {
  font-family: var(--serif);
  font-size: clamp(1.75rem, 3.5vw, 2.35rem);
  line-height: 1.2; margin: 0 0 .75rem; color: var(--header);
}
article h2 {
  font-family: var(--serif); font-size: 1.45rem; margin: 2rem 0 .75rem;
  color: var(--header); border-bottom: 1px solid var(--border); padding-bottom: .35rem;
}
article h3 { font-size: 1.12rem; margin: 1.4rem 0 .5rem; color: var(--fairway); }
article p, article ul, article ol { margin: 0 0 1rem; }
article ul, article ol { padding-left: 1.25rem; }
article li { margin: .25rem 0; }
.meta {
  color: var(--muted); font-size: .92rem; margin-bottom: 1.25rem;
}
.callout {
  background: #e9f5ee; border-left: 4px solid var(--fairway);
  padding: .9rem 1rem; border-radius: 0 var(--radius) var(--radius) 0;
  margin: 1.25rem 0; color: var(--ink);
}
.callout strong { color: var(--header); }
.sources {
  background: var(--bg-card); border: 1px dashed var(--border);
  padding: 1rem 1.1rem; border-radius: var(--radius); margin-top: 2rem;
}
.sources h2 { border: 0; margin-top: 0; font-size: 1.15rem; }
table {
  width: 100%; border-collapse: collapse; margin: 1rem 0 1.5rem;
  font-size: .95rem; background: var(--bg-card);
  border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden;
}
th, td { text-align: left; padding: .65rem .75rem; border-bottom: 1px solid var(--border); vertical-align: top; }
th { background: #d8f3dc; font-size: .82rem; text-transform: uppercase; letter-spacing: .04em; color: var(--header); }
tr:last-child td { border-bottom: 0; }
.table-wrap { overflow-x: auto; margin: 1rem 0 1.5rem; }
.table-wrap table { margin: 0; }

.site-footer {
  border-top: 1px solid var(--border); padding: 2rem 0 2.5rem;
  color: var(--muted); font-size: .92rem; background: #e3f2e9;
}
.site-footer a { color: var(--accent); }
.disclaimer { max-width: 48rem; }

.btn {
  display: inline-block; background: var(--fairway); color: #fff !important;
  text-decoration: none; padding: .55rem 1rem; border-radius: 999px;
  font-weight: 600; font-size: .95rem;
}
.btn:hover { background: var(--fairway-deep); }
.btn-secondary {
  background: transparent; color: var(--fairway) !important;
  border: 1px solid var(--fairway); margin-left: .4rem;
}
.btn-row { display: flex; flex-wrap: wrap; gap: .5rem; margin-top: 1.25rem; }

.checklist li { margin: .45rem 0; }
.section-label { margin: 2rem 0 .75rem; font-family: var(--serif); color: var(--header); }

@media (max-width: 640px) {
  .site-header .bar { align-items: flex-start; }
  th, td { padding: .55rem .5rem; font-size: .9rem; }
}

.callout.featured-gear {
  border-left: 4px solid var(--accent);
  background: linear-gradient(180deg, #ffffff 0%, #fff4e6 100%);
}
.callout.featured-gear .partner-cta {
  display: inline-block;
  margin-top: .35rem;
  font-size: .9rem;
  color: var(--muted);
  font-style: italic;
}

.related-rail, .continue-learning {
  margin: 2rem 0 1.5rem;
  padding: 1.1rem 1.25rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.continue-learning {
  border-left: 4px solid var(--accent);
}
.related-rail h2, .continue-learning h2 {
  margin: 0 0 0.35rem;
  font-size: 1.15rem;
}
.related-lede {
  margin: 0 0 0.75rem;
  color: var(--muted);
  font-size: 0.95rem;
}
.related-list {
  margin: 0;
  padding-left: 1.2rem;
}
.related-list li {
  margin: 0.35rem 0;
}
.related-meta {
  color: var(--muted);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-left: 0.35rem;
}
.cluster-hub a { white-space: nowrap; }
.cluster-path .card h3 { font-size: 1.05rem; }

/* —— Flight path chart tool —— */
.flight-hero .meta { margin-top: .75rem; }
.flight-layout {
  display: grid;
  gap: 1.25rem;
  grid-template-columns: minmax(260px, 340px) 1fr;
  margin: 1.25rem 0 2rem;
  align-items: start;
}
@media (max-width: 860px) {
  .flight-layout { grid-template-columns: 1fr; }
}
.flight-filters .field,
.flight-filters .field-row label {
  display: flex; flex-direction: column; gap: .3rem;
  font-size: .88rem; font-weight: 600; color: var(--header);
  margin-bottom: .75rem;
}
.flight-filters input[type="search"],
.flight-filters input[type="number"],
.flight-filters select {
  font: inherit; font-weight: 500; color: var(--ink);
  padding: .5rem .65rem; border: 1px solid var(--border);
  border-radius: 8px; background: #fff;
}
.flight-filters .field-row {
  display: grid; grid-template-columns: 1fr 1fr; gap: .5rem;
}
.flight-filters .check {
  flex-direction: row; align-items: center; gap: .5rem; font-weight: 500;
}
.flight-filters .check input { width: 1.05rem; height: 1.05rem; }
.filter-meta { color: var(--muted); font-size: .88rem; margin: .25rem 0 .5rem; }
.disc-list {
  max-height: 420px; overflow: auto;
  border: 1px solid var(--border); border-radius: 8px;
  background: #f8fcf9;
}
.disc-item {
  display: grid; width: 100%; text-align: left;
  border: 0; border-bottom: 1px solid var(--border);
  background: transparent; padding: .65rem .7rem; cursor: pointer;
  font: inherit; color: inherit;
}
.disc-item:last-child { border-bottom: 0; }
.disc-item:hover, .disc-item.active { background: #e9f5ee; }
.disc-item.active { box-shadow: inset 3px 0 0 var(--accent); }
.di-name { font-weight: 700; color: var(--header); }
.di-mfr { font-size: .88rem; color: var(--fairway); }
.di-meta { font-size: .82rem; color: var(--muted); }
.flight-stage .stage-head {
  display: flex; flex-wrap: wrap; justify-content: space-between;
  gap: .75rem; align-items: flex-start; margin-bottom: .75rem;
}
.flight-stage h2 { margin: 0 0 .25rem; font-family: var(--serif); color: var(--header); font-size: 1.45rem; border: 0; }
.flight-stage .muted { color: var(--muted); margin: 0; font-size: .95rem; }
.release-toggle { display: flex; gap: .35rem; flex-wrap: wrap; }
.chip {
  border: 1px solid var(--border); background: #fff; color: var(--fairway);
  border-radius: 999px; padding: .35rem .75rem; font: inherit; font-weight: 600;
  cursor: pointer;
}
.chip.active, .chip:hover {
  background: var(--fairway); color: #fff; border-color: var(--fairway);
}
.numbers {
  display: grid; grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: .5rem; margin: .75rem 0 1rem;
}
.numbers div {
  background: #fff4e6; border: 1px solid #ffd7a8; border-radius: 8px;
  padding: .55rem .4rem; text-align: center;
}
.numbers span {
  display: block; font-size: .72rem; letter-spacing: .06em;
  text-transform: uppercase; color: var(--muted); font-weight: 700;
}
.numbers strong { font-size: 1.35rem; color: var(--accent); }
.chart-wrap { margin: .5rem 0 1rem; }
#fc-svg { width: 100%; max-width: 420px; height: auto; display: block; margin: 0 auto; border-radius: 12px; box-shadow: var(--shadow); }
.chart-caption { font-size: .88rem; color: var(--muted); text-align: center; margin: .65rem 0 0; }
.cite { font-size: .92rem; color: var(--muted); }
.related-inline { font-size: .95rem; }
.how-chart { margin: 1.5rem 0; }
.how-chart h2 { margin-top: 0; font-family: var(--serif); color: var(--header); border-bottom: 1px solid var(--border); padding-bottom: .35rem; }
.how-chart ol { margin: 0 0 1rem; padding-left: 1.25rem; }