/* ============================================================
   Elequate Brand Guide — shared layout.
   Art-forward: code/mono reserved for spec pages only.
   ============================================================ */

:root {
  --bg: #fafbfd;
  --surface: #ffffff;
  --rule: rgba(30, 58, 95, 0.08);
  --rule-strong: rgba(30, 58, 95, 0.16);
  --ink: #0c1f38;
  --ink-muted: #556f8a;
  --code-bg: #eef5fa;
  --doc-max: 1240px;
}

html, body { background: var(--bg); color: var(--ink); scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-feature-settings: "ss01","cv11","cv02","cv03";
}
* { box-sizing: border-box; }
img { max-width: 100%; display: block; }
code, .mono { font-family: var(--font-mono); }

/* ---------- Left rail (collapsible) ---------- */
.bg-shell { display: grid; grid-template-columns: 72px 1fr; min-height: 100vh; transition: grid-template-columns .3s cubic-bezier(0.16,1,0.3,1); }
.bg-shell:hover,
.bg-shell:focus-within { grid-template-columns: 260px 1fr; }

.bg-rail {
  position: sticky; top: 0; height: 100vh;
  padding: 24px 14px;
  border-right: 1px solid var(--rule);
  background: var(--surface);
  overflow: hidden;
  z-index: 20;
  transition: padding .3s ease;
}
.bg-shell:hover .bg-rail,
.bg-shell:focus-within .bg-rail { padding: 28px 22px 28px 28px; overflow-y: auto; }

.bg-rail-brand { display: flex; align-items: center; gap: 12px; margin-bottom: 28px; }
.bg-rail-brand .brand-mark { display: block; flex-shrink: 0; }
.bg-rail-brand .brand-mark.icon { width: 28px; height: 28px; }
.bg-rail-brand .brand-mark.word { height: 22px; width: auto; display: none; }
.bg-shell:hover .bg-rail-brand .brand-mark.icon,
.bg-shell:focus-within .bg-rail-brand .brand-mark.icon { display: none; }
.bg-shell:hover .bg-rail-brand .brand-mark.word,
.bg-shell:focus-within .bg-rail-brand .brand-mark.word { display: block; }
.bg-rail-brand > div { opacity: 0; transition: opacity .2s ease; white-space: nowrap; }
.bg-shell:hover .bg-rail-brand > div,
.bg-shell:focus-within .bg-rail-brand > div { opacity: 1; }
.bg-rail-brand .wm { font-size: 15px; font-weight: 800; letter-spacing: -0.01em; color: var(--ink); }
.bg-rail-brand .ver { font-size: 11px; color: var(--ink-muted); letter-spacing: 0.02em; font-weight: 500; }

.bg-rail-section { margin-top: 22px; }
.bg-rail-section h6 {
  font-size: 11px; font-weight: 700;
  letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--ink-muted);
  margin: 0 0 8px; padding-left: 4px;
  opacity: 0; transition: opacity .2s ease;
  white-space: nowrap;
}
.bg-shell:hover .bg-rail-section h6,
.bg-shell:focus-within .bg-rail-section h6 { opacity: 1; }

.bg-rail a {
  display: flex; align-items: center; gap: 10px;
  padding: 8px 8px; border-radius: 6px;
  color: var(--ink); text-decoration: none;
  font-size: 13.5px; font-weight: 500;
  line-height: 1.3;
  transition: background .15s ease, color .15s ease;
  white-space: nowrap;
  overflow: hidden;
}
.bg-rail a:hover { background: var(--code-bg); color: var(--blueprint-dark); }
.bg-rail a .n {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--blueprint-blue); width: 24px; flex-shrink: 0;
  font-weight: 700;
  text-align: center;
}
.bg-rail a .lbl {
  opacity: 0; transition: opacity .2s ease;
}
.bg-shell:hover .bg-rail a .lbl,
.bg-shell:focus-within .bg-rail a .lbl { opacity: 1; }
.bg-rail a.is-active { background: #e8f4fa; color: var(--blueprint-dark); font-weight: 600; }
.bg-rail a.is-active .n { color: var(--blueprint-blue); }

/* ---------- Main column ---------- */
.bg-main { padding: 0; min-width: 0; }
.bg-wrap { max-width: 1120px; padding: 0 48px; margin: 0 auto; }

.bg-section { padding: 120px 0 40px; }
.bg-section + .bg-section { border-top: 1px solid var(--rule); }

.bg-section-head {
  display: grid; grid-template-columns: 130px 1fr; gap: 32px;
  align-items: baseline;
  margin-bottom: 48px;
}
.bg-section-num {
  padding-top: 18px;
  display: flex; flex-direction: column; gap: 8px;
  color: var(--blueprint-blue);
  line-height: 1;
}
.bg-section-num .sn-num {
  font-family: var(--font-mono);
  font-size: 34px; font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--blueprint-dark);
}
.bg-section-num .sn-sep {
  width: 28px; height: 2px; background: var(--blueprint-blue);
  border-radius: 2px;
}
.bg-section-num .sn-lbl {
  font-size: 10.5px; font-weight: 700;
  letter-spacing: 0.18em;
  color: var(--blueprint-blue);
}
.bg-section-title {
  font-size: clamp(40px, 4.4vw, 60px);
  font-weight: 900;
  letter-spacing: -0.035em;
  line-height: 1.02;
  color: var(--ink);
  margin: 0;
}
.bg-section-title em { font-style: normal; color: var(--blueprint-blue); }
.bg-section-lede {
  grid-column: 2;
  margin-top: 18px; max-width: 720px;
  font-size: 18px; line-height: 1.55; color: #2a4566;
}
.bg-section-body { padding-left: 108px; }

/* Sub headings */
.bg-sub {
  display: flex; align-items: baseline; gap: 14px;
  margin: 64px 0 24px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--rule);
}
.bg-sub .tag {
  font-size: 11px; font-weight: 700;
  letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--blueprint-blue);
}
.bg-sub h3 {
  font-size: 22px; font-weight: 700;
  letter-spacing: -0.01em; color: var(--ink);
  margin: 0;
}
.bg-sub .right { margin-left: auto; font-size: 12px; color: var(--ink-muted); font-weight: 500; }

.bg-muted { color: var(--ink-muted); }
.bg-code {
  font-family: var(--font-mono);
  font-size: 12.5px;
  background: var(--code-bg);
  color: var(--blueprint-dark);
  padding: 1px 6px; border-radius: 4px;
}

/* Reveal-on-scroll */
.reveal { opacity: 0; transform: translateY(28px); transition: opacity .8s cubic-bezier(0.16,1,0.3,1), transform .8s cubic-bezier(0.16,1,0.3,1); }
.reveal.in { opacity: 1; transform: none; }

/* Card primitive */
.bg-card { background: var(--surface); border: 1px solid var(--rule); border-radius: 14px; overflow: hidden; }
.bg-card.dark { background: #0d1e36; color: #fff; border-color: rgba(255,255,255,0.08); }

/* Chips */
.bg-pill {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 6px 12px; border-radius: 100px;
  font-size: 11px; font-weight: 700;
  letter-spacing: 0.10em; text-transform: uppercase;
  background: #e8f4fa; color: var(--blueprint-dark);
  border: 1px solid rgba(45,125,179,0.18);
}
.bg-pill .dot { width: 7px; height: 7px; border-radius: 50%; background: var(--cyan-accent); box-shadow: 0 0 0 3px rgba(33,192,255,0.22); }

/* Mobile */
@media (max-width: 960px) {
  .bg-shell { grid-template-columns: 1fr !important; }
  .bg-rail { position: sticky; top: 0; height: auto; border-right: none; border-bottom: 1px solid var(--rule); padding: 14px 20px !important; overflow-x: auto !important; overflow-y: hidden; white-space: nowrap; }
  .bg-rail-brand > div, .bg-rail-section h6, .bg-rail a .lbl { opacity: 1 !important; }
  .bg-wrap { padding: 0 24px; }
  .bg-section { padding: 56px 0 24px; }
  .bg-section-head { grid-template-columns: 1fr; gap: 10px; }
  .bg-section-lede { grid-column: 1; }
  .bg-section-body { padding-left: 0; }
  .bg-rail-brand { margin: 0; }
  .bg-rail-section { display: inline-block; margin: 0 14px 0 0; }
  .bg-rail-section h6 { display: none; }
  .bg-rail a { display: inline-flex; padding: 4px 8px; }
  .bg-rail a .n { display: none; }
}